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Littérature scientifique sur le sujet « QWs »

Auteur : Grafiati

Publié le 4 juin 2021

Mis à jour le 14 février 2022

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Articles de revues sur le sujet "QWs"

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Žurauskienė, N., S. Ašmontas, A. Dargys, J. Kundrotas, G. Janssen, E. Goovaerts, Stanislovas Marcinkevičius, Paul M. Koenraad, J. H. Wolter et R. P. Leon. « Semiconductor Nanostructures for Infrared Applications ». Solid State Phenomena 99-100 (juillet 2004) : 99–108. http://dx.doi.org/10.4028/www.scientific.net/ssp.99-100.99.

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We present the results of time-resolved photoluminescence (TRPL) and optically detected microwave resonance (ODMR) spectroscopy investigations of semiconductor quantum dots and quantum wells. The ODMR spectra of InAs/GaAs QDs were detected via modulation of the total intensity of the QDs emission induced by 95 GHz microwave excitation and exciton fine structure was studied. Very long life times (up to 10 ns) of photoexcited carriers were observed in this system using TRPL at low temperatures and excitation intensities promising higher responsitivity of such QDs for quantum dot infrared photodetector development. The effects of proton and alpha particles irradiation on carrier dynamics were investigated on different InGaAs/GaAs, InAlAs/AlGaAs and GaAs/AlGaAs QD and QW systems. The obtained results demonstrated that carrier lifetimes in the QDs are much less affected by proton irradiation than that in QWs. A strong influence of irradiation on the PL intensity was observed in multiple QWs after high-energy alpha particles irradiation.

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Kawazu, Takuya. « Valence Band Mixing in GaAs/AlGaAs Quantum Wells Adjacent to Self-Assembled InAlAs Antidots ». Journal of Nanomaterials 2019 (28 avril 2019) : 1–7. http://dx.doi.org/10.1155/2019/5349291.

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Optical properties of GaAs/AlGaAs quantum wells (QWs) in the vicinity of InAlAs quantum dots (QDs) were studied and compared with a theoretical model to clarify how the QD strain affects the electronic states in the nearby QW. In0.4Al0.6As QDs are embedded at the top of the QWs; the QD layer acts as a source of strain as well as an energy barrier. Photoluminescence excitation (PLE) measurements showed that the QD formation leads to the increase in the ratio Ie-lh/Ie-hh of the PLE intensities for the light hole (lh) and the heavy hole (hh), indicating the presence of the valence band mixing. We also theoretically calculated the hh-lh mixing in the QW due to the nearby QD strain and evaluated the PLE ratio Ie-lh/Ie-hh.

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Yunovich, A. E., V. E. Kudryashov, A. N. Turkin, A. N. Kovalev et F. I. Manyakhin. « Electroluminescence Properties of InGaN/AlGaN/GaN Light Emitting Diodes with Quantum Wells ». MRS Internet Journal of Nitride Semiconductor Research 4, S1 (1999) : 659–64. http://dx.doi.org/10.1557/s1092578300003215.

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Electroluminescence spectra of light-emitting diodes based on InGaN/AlGaN/GaN heterostructures with single and multiple quantum wells (QWs) are analyzed by models of radiative recombination in 2D-structures with band tails. Equations of the model fit spectra quite good in a wide range of currents. Parameters of the fit are discussed and compared for single and multiple QWs. Tunnel effects play a sufficient role in blue LEDs with single QWs at low currents; they can be neglected in LEDs with multiple QWs. A new spectral band was detected at the high energy side of the spectra of green LEDs with multiple QWs; it is attributed with large scale inhomogenities of In distribution in InGaN QWs.*)

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Wysham, Carol H., Julio Rosenstock, Marion L. Vetter, Hui Wang, Elise Hardy et Nayyar Iqbal. « Further improvement in glycemic control after switching from exenatide two times per day to exenatide once-weekly autoinjected suspension in patients with type 2 diabetes : 52-week results from the DURATION-NEO-1 study ». BMJ Open Diabetes Research & ; Care 8, n^o 1 (octobre 2020) : e000773. http://dx.doi.org/10.1136/bmjdrc-2019-000773.

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IntroductionInvestigate the effects of switching from two times per day exenatide to once-weekly exenatide administered by autoinjector (exenatide once-weekly suspension by autoinjector (QWS-AI)) or treatment with exenatide QWS-AI for 1 year.Research design and methodsIn this phase III open-label study, adults with type 2 diabetes were randomized to receive exenatide QWS-AI (2 mg) or exenatide two times per day (5 mcg for 4 weeks, followed by 10 mcg) for 28 weeks. During a subsequent non-randomized 24-week extension, patients who received exenatide two times per day were switched to exenatide QWS-AI and those randomized to exenatide QWS-AI continued this treatment. Efficacy measures included changes from baseline in glycated hemoglobin (A1C), fasting plasma glucose (FPG), and body weight.ResultsIn total, 315 patients (mean baseline A1C of 8.5%) completed the initial 28 weeks of randomized treatment with exenatide QWS-AI (n=197) or exenatide two times per day (n=118) and were included in the 24-week extension (mean A1C of 7.0% and 7.3%, respectively, at week 28). From weeks 28–52, patients who switched from exenatide two times per day to exenatide QWS-AI had additional A1C reductions of approximately 0.5% (mean A1C change from baseline of –1.4% at week 52) and further reductions from baseline in FPG. Patients who continued exenatide QWS-AI treatment for 52 weeks showed clinically relevant A1C reductions (mean A1C change from baseline of –1.3% at week 52). Body-weight reductions achieved through week 28 were sustained at week 52 in both groups. There were no unexpected safety concerns or changes in the safety profile among patients who switched from exenatide two times per day to exenatide QWS-AI or those who continued exenatide QWS-AI treatment for 52 weeks.ConclusionsSwitching from exenatide two times per day to exenatide QWS-AI resulted in further A1C reductions and maintenance of earlier decreases in body weight, while continued therapy with exenatide QWS-AI for 52 weeks maintained A1C and body-weight reductions, without additional safety or tolerability concerns.Trial registration numberNCT01652716.

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Santiago, Svette Reina Merden, Septem P. Caigas, Tzu-Neng Lin, Chi-Tsu Yuan, Ji-Lin Shen, Ching-Hsueh Chiu et Hao-Chung Kuo. « Tunnel injection from WS2 quantum dots to InGaN/GaN quantum wells ». RSC Advances 8, n^o 28 (2018) : 15399–404. http://dx.doi.org/10.1039/c7ra13108a.

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In this manuscript, an effective tunnel-injection structure, in which the WS₂ quantum dots (QDs) act as the electron injector and the InGaN quantum wells (QWs) act as the light emitters, separated by GaN barriers.

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Минтаиров, С. А., Н. А. Калюжный, А. М. Надточий, М. В. Максимов, В. Н. Неведомский, Л. А. Сокура, С. С. Рувимов, М. З. Шварц et А. Е. Жуков. « Многослойные InGaAs-гетероструктуры "квантовая яма-точки" в фотопреобразователях на основе GaAs ». Физика и техника полупроводников 52, n^o 10 (2018) : 1131. http://dx.doi.org/10.21883/ftp.2018.10.46452.8879.

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AbstractGaAs photovoltaic converters containing quantum well-dot (QWD) heterostructures are studied. The QWD properties are intermediate between those of quantum wells (QWs) and quantum dots. The QWDs are obtained by the epitaxial deposition of In_0 . 4Ga_0 . 6As with a nominal thickness of 8 single layers by metal-organic vapor phase epitaxy. QWDs are a dense array of elastically strained islands that localize carriers in three directions and are formed by a local increase in the indium concentration and/ or InGaAs-layer thickness. There are two quantum-well levels of varied nature in structures with QWDs. These levels are manifested in the spectral characteristics of GaAs photovoltaic converters. A short-wavelength peak with a maximum at around 935 nm is associated with absorption in the residual QW, and the long-wavelength peak (1015–1030 nm) is due to absorption in the QWDs. Investigation by transmission electron microscopy demonstrates that an increase in the number of InGaAs layers leads to stronger elastic stresses, which, in turn, increases the carrier confinement energy in the QWDs and lead to a corresponding long-wavelength shift of the internal quantum efficiency spectrum.

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Chen, Ping, Young Jae Park, Yuh-Shiuan Liu, Theeradetch Detchprohm, P. Douglas Yoder, Shyh-Chiang Shen et Russell D. Dupuis. « Epitaxial Growth and Optically Pumped Stimulated Emission in AlGaN/InGaN Ultraviolet Multi-Quantum-Well Structures ». Journal of Electronic Materials 49, n^o 4 (8 janvier 2020) : 2326–31. http://dx.doi.org/10.1007/s11664-019-07932-x.

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AbstractThe thermal effect of the growth temperature on interface morphology and stimulated emission in ultraviolet AlGaN/InGaN multiple quantum wells (MQWs) are experimentally investigated. During the MOCVD epitaxial growth of AlGaN/InGaN MQWs, the ramping rate from a lower temperature for InGaN quantum wells (QWs) to a higher one for AlGaN quantum barriers (QBs) is intentionally changed from 1.0°C/s to 4.0°C/s. Atomic force microscopy images show that the surface morphology of InGaN QWs, which is improved by a thermal effect when the growth temperature rises to the set value of the AlGaN QBs, varies with different temperature ramping rates. The results of stimulated emission indicate that the threshold pumping power density of MQWs is decreased with increasing temperature ramping rate from 1.0°C/s to 3.0°C/s and then slightly increased when the ramping rate is 4.0°C/s. This phenomenon is believed to result from the thermal degradation effect during the temperature ramp step. A long-time high-temperature annealing will reduce the density of indium-rich microstructures as well as the corresponding localized state density, which is assumed to contribute to the radiative recombination in the InGaN QWs. Given the great difference between optimal growth temperatures for AlGaN and InGaN layers, a higher ramping rate would be more appropriate for the growth of ultraviolet AlGaN/InGaN MQWs.

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Funato, Mitsuru, et Yoichi Kawakami. « Semipolar III Nitride Semiconductors : Crystal Growth, Device Fabrication, and Optical Anisotropy ». MRS Bulletin 34, n^o 5 (mai 2009) : 334–40. http://dx.doi.org/10.1557/mrs2009.96.

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AbstractSemipolar InGaN/GaN quantum wells (QWs) are quite attractive as visible light emitters. One of the reasons is that a better optical transition probability is expected because of weaker internal electric fields, compared to conventional polar QWs. In addition, in-plane optical polarization anisotropy, which is absent in conventional QWs, is another relevant property because it affects device design and also may provide a means for novel applications. We revealed that the in-plane optical anisotropy in semipolar QWs switched from one direction perpendicular to the [0001] crystal axis to the perpendicular direction as the In composition increases. This is a property unique to semipolar QWs and enables, for example, to make cavity mirrors of laser diodes by cleavage. In this article, we describe the concept of semipolar planes and fabrication of high-quality epitaxial films for semipolar QWs. Furthermore, we discuss device fabrication and optical polarization anisotropy.

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Danielson, Andrew J. « On the History and Evolution of Qws : The Portrait of a First Millennium BCE Deity Explored through Community Identity ». Journal of Ancient Near Eastern Religions 20, n^o 2 (16 avril 2021) : 113–89. http://dx.doi.org/10.1163/15692124-12341314.

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Abstract This article explores the history and evolution of the deity Qws through a study of the communities affiliated with Qws, presenting also a current collection of all inscriptional references to this deity. Diachronic and spatial analyses of the references reveal nuanced insights into how Qws was understood by his adherents, as well as the patterns of behavior, linguistic practices, and identities that marked these communities. The attestations of Qws demonstrate the deity’s relative obscurity during the Late Bronze Age, a rapid rise in inscriptional popularity among persons associated with the region of Edom during the late Iron Age, and a regional perpetuation of attestation following the dissolution of the Iron Age southern Levantine polities. Furthermore, attestations of Qws among diasporic community’s present insights into the shifting identities and cultic practices of the immigrant communities affiliated with the deity.

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Geng, Zhenduo, et Yuping Wang. « Optical properties in wurtzite InGaN staggered quantum wells ». Modern Physics Letters B 29, n^o 15 (10 juin 2015) : 1550076. http://dx.doi.org/10.1142/s0217984915500761.

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The polarization field effects on exciton states and optical properties are studied theoretically in the wurtzite (WZ) In x Ga 1-x N / In y Ga 1-y N staggered quantum wells (QWs). Numerical results show that the polarization field effects are obvious on the Stark shifts of the exciton binding energy, the oscillator strength and the emission wavelength when the well width and Indium content y increase in the symmetric staggered QWs. However, the influences of In x Ga 1-x N well layer are remarkable on exciton states and optical properties when the Indium concentration y is small in the asymmetric staggered QWs. In addition, the ground state linear optical susceptibility is also investigated in the WZ staggered QWs.

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Thèses sur le sujet "QWs"

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Tomlinson, Andrew Michael. « Terahertz detection and electric field domains in multiple quantum wells ». Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302363.

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Hussain, Sakhawat. « Propriétés optiques et structurales de dispositifs luminescents contenant des puits quantiques (In,Ga)N à forte concentration en Indium et émettant dans le vert et le jaune ». Thesis, Nice, 2014. http://www.theses.fr/2014NICE4123/document.

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Le but de cette thèse a été d'étudier les propriétés structurales et optiques de puits quantiques (PQs) d’InGaN/(Al)GaN obtenus par épitaxie en phase vapeur d’organométalliques. Différentes approches ont été mises en œuvre pour atteindre une émission dans le vert-jaune: la première utilisant une concentration d'indium ≥ 20% avec un PQ d’InGaN d’épaisseur <3.0 nm et vice versa. L'effet d'une couche d’encapsulation a également été étudié. Les techniques de microscopie à force atomique, de diffraction des rayons X, de photoluminescence (PL) et surtout de microscopie électronique à transmission (MET) ont été utilisées pour caractériser ces structures. Les épaisseurs des PQs et les compositions en indium ont été déterminées par le traitement numérique des franges de réseau dans les images MET haute résolution en section transverse. Un traitement original a été développé pour analyser quantitativement les fluctuations de l’épaisseur des PQs. L'analyse structurale des PQs ayant une composition en In élevé a montré que les défauts structuraux sont créés dans les PQs. La nature et la densité de ces défauts ont été déterminées et différents mécanismes pour leur formation ont été proposés. Il a également été montré que quelques monocouches d’encapsulation de GaN ou d’AlGaN déposées à la température de croissance des PQs limitent l’évaporation et/ou la diffusion d’indium. Ce procédé permet d’étendre la longueur d'onde d'émission avec une réduction de la dégradation de l'efficacité de la PL. Mon travail propose quelques pistes afin d'obtenir un bon compromis entre les paramètres contradictoires qui régissent l'efficacité des PQs émettant dans le vert-jaune
The goal of this thesis was to study the structural and optical properties of InGaN/(Al)GaN multiple QWs grown by metal organic chemical vapor deposition. Different approaches have been implemented to achieve green-yellow emission: high indium concentration (≥ 20%) with low InGaN QW thickness (< 3 nm) or vice versa. Moreover, the effect of a capping layer on top of the QWs has also been investigated. Atomic force microscopy, X-ray diffraction, room temperature photoluminescence (RTPL) and mainly transmission electron microscopy (TEM) techniques have been used to characterize these structures. The QW thicknesses and indium compositions have been determined by digital processing of lattice fringes in cross-sectional high resolution TEM images. An original treatment has been developed to analyze quantitatively InGaN QW thickness fluctuations. The structural analysis of multiple QWs with high indium composition has shown that structural defects are created in the QWs. The nature and the density of these defects have been determined and different mechanisms for their formation have been proposed. It has also been shown that a few monolayers of AlGaN or GaN capping layers deposited at the InGaN QW growth temperature prohibited indium evaporation and/or diffusion. It therefore helps to extend the emission wavelength with a reduced degradation of the RTPL efficiency. My work offers a few ways to obtain a good compromise between the conflicting parameters that govern the efficiency of QWs emitting in the green-yellow spectrum range

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Ehsaan, Muhammad. « Development & ; exploitation of gene tools for metabolic engineering in saccharolytic Clostridia ». Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/30923/.

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C. acetobutylicum A TCC 824 is a well characterized microorganism known for its ability to produce solvents using the Acetone-Butanol-Ethanol (AB E) fermentation process. It can utilize a variety of Cs and C6 sugars, but cannot directly access the complex lignocellulose plant cell wall material which is the most abundant source of carbon in nature. Sophisticated genetic tools are required to enhance the substrate utilisation ability of the organism by incorporating synthetic operons using a synthetic biology approach. Efficient tools were developed for making precise alterations to the C. acetobutylicum genome using either heterologous pyrE or codA genes as counterselection markers. In the case of the former, the utility of the method was also demonstrated in Clostridium difficile. The robustness and reliability of the methods were demonstrated through the creation of in-frame deletions in two genes (spoOA, amylase) using pyrE and also two genes (Cac1502 and Cac2071 (spoOA) using codA. The pyrE system is reliant on the initial creation of a pyre deletion mutant using Allele Coupled Exchange (ACE), that is auxotrophic for uracil and resistant to fluoroorotic acid (FOA). This enables the subsequent modification of target genes by allelic exchange using a heterologous pyre allele from C. sporogenes as a counter-/negative-selection marker in the presence of FOA. Following modification of the target gene, the strain created is rapidly returned to uracil prototrophy using ACE, allowing mutant phenotypes to be characterised in a pyrE proficient background. Crucially, wild-type copies of the inactivated gene may be introduced into the genome using ACE concomitant with correction of the pyrE allele. This allows complementation studies to be undertaken at an appropriate gene dosage, as opposed to the use of multicopy autonomous plasmids. The rapidity of the 'correction' method (5-7 days) makes pyrE strains attractive hosts for mutagenesis studies.

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Liew, Fung Min. « Metabolic engineering of Clostridium autoethanogenum ». Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32451/.

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Gas fermentation has emerged as a promising technology that converts waste gases containing CO, CO2 and H2 (also known as syngas) into fuels and chemical commodities. Employed by LanzaTech Inc., Clostridium autoethanogenum is an industrial acetogen that converts gases into ethanol, 2,3-butanediol, acetate, and lactate. Metabolic engineering offers unique opportunities to eliminate side-products, synthesize novel, high-value molecules as diversification strategies, and increase productivities of natural products. However, there had been no scientific reports of genetic manipulation of this acetogen so the overall goal of this PhD project was to develop genetic tools for this gas-utilizing microorganism and construct a hyper-ethanol producing strain via metabolic engineering. The formulation of electroporation and conjugation procedures allowed exogenous DNA to be routinely introduced into the bacterial host. ClosTron mutagenesis and Allele-Coupled Exchange (ACE) techniques were fully exemplified in this bacterium during the construction of knockout, in-frame deletion, and overexpression mutants. Carbon monoxide dehydrogenases (cooS1, cooS2 and acsA) were specifically targeted to elucidate their roles in supporting CO oxidation and carbon fixation. In the ethanol formation pathway, inactivation of bi-functional aldehyde/alcohol dehydrogenases (adhE1 and adhE2) impaired growth on pure CO but elevated ethanol titres. Conversely, inactivation of the more highly expressed aldehyde:ferredoxin oxidoreductase (aor1), but not the weakly expressed aor2, significantly reduced ethanol production, highlighting the importance of aor1 in autotrophic ethanol formation. A double KO mutant of aor1 and aor2 was also generated via ClosTron mutagenesis and pyrE-mediated allelic exchange. In an effort to engineer a robust biocatalyst, the native chaperone systems groESL and/or grpE-dnaK-dnaJ were overexpressed in C. autoethanogenum, resulting in enhanced tolerance towards ethanol, heat and salts. In summary, this study demonstrated the genetic tractability of C. autoethanogenum and revealed gene targets for future metabolic engineering of a hyper-ethanol producing acetogen.

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qqqq et Cehn. « qwe ». 碩士, 國立中正大學, 1999. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22099CCU00045001%22.&searchmode=basic.

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Bchini, Tarek. « Gestion de la Mobilité, de la Qualité de Service et Interconnexion de Réseaux Mobiles de Nouvelle Génération ». Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0016/document.

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Avec l’évolution rapide des technologies réseaux et télécoms radios mobiles, les chercheurs sont actuellement en train de préparer l’arrivée d’une nouvelle génération baptisée 4G. Le réseau de 4ème génération qui est encore l’objet de travaux de recherche vise à améliorer l’efficacité spectrale et à augmenter la capacité de gestion du nombre des mobiles dans une même cellule. Il tend à offrir des débits élevés en situation de mobilité à grande ou faible vitesse. Il vise aussi à permettre et à faciliter l’interconnexion et l’interopérabilité entre différentes technologies existantes en rendant transparent à l’utilisateur le passage entre les réseaux. Enfin, il vise à éviter l’interruption des services durant le transfert intercellulaire, et à basculer l’utilisation vers le tout IP. Dans ce contexte, nous nous sommes intéressés en premier lieu aux problématiques de la QoS en situation de mobilité au sein d’une technologie candidate à la 4G (WiMAX mobile) pour du trafic temps-réel. Pour cela, nous avons comparé la performance de plusieurs protocoles de mobilité dans le contexte du Handover de niveau 2 et de niveau 3 et plus. Nous avons pour cela fait varier les modèles de mobilité, les configurations et les scénarios. Enfin, nous avons modélisé un algorithme décisionnel qui gère le Handover dans le WiMAX mobile en fonction de plusieurs paramètres d’entrées. Au travers de ces études, nous avons dégagé des protocoles de mobilité qui offrent un niveau de QoS acceptable pour un trafic temps-réel dans le cadre des scénarios envisagés. En deuxième lieu, nous nous sommes concentrés sur les problèmes d’interconnexion et d’interopérabilité entre les réseaux en tenant compte de la mobilité et du Handover vertical entre deux technologies. Pour cela, nous avons proposé de comparer des protocoles de mobilité puis de les combiner afin de diminuer les délais des trafics temps-réel au cours du Handover. Au niveau de l’interconnexion, nous avons proposé des modèles entre WiMAX mobile et de nombreux autres standards (802.11e, UMTS, DVB-S/RCS, LTE). Outre les solutions d’interconnexion, nous avons également mis en évidence la ou les combinaisons de protocoles de gestion de la mobilité qui permettent de garantir de la QoS
With the rapid evolution of mobile radio telecommunications and networks technologies, researchers are currently preparing the arrival of a new generation called 4G. The 4th generation network aims to improve spectral efficiency and increase capacity to manage a large number of mobiles in a cell. It tries to provide high flow rates under high or low mobility. It also aims to enable and facilitate the interconnection and the interoperability between different technologies allowing transparent transition between networks. Finally, it aims to avoid interruption of services during the handover, and to switch an all-IP system. In this context, we are concerned first with QoS and mobility issues in Mobile WiMAX for the real-time traffic. We compared the performance of several mobility protocols in the context of the level 2 and level 3+ handovers. Several mobility models, configurations and scenarios were considered. Finally, we modeled a decision algorithm that manages the handover in mobile WiMAX based on several input parameters.Through these studies, we have identified mobility protocols that provide an acceptable QoS level for real-time traffic under the proposed scenarios. Secondly, we focused on the problems of interconnection and interoperability between networks, taking into account the mobility and vertical handovers between two technologies. For this, we proposed to compare mobility protocols or combine them to reduce delays for real-time traffic during the handover. We also proposed interconnection models between mobile WiMAX and many other standards (802.11e, UMTS, DVB-S/RCS, LTE). Besides interconnection solutions, we also highlighted the combination or combinations of management mobility protocols that can guarantee QoS

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Islam, Mohammad Shahidul, et Syed Nasir Mehdi. « How Different QoS Mechanisms Affect VoIP QoS Metrics ». Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15337.

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Voice over Internet Protocol (VoIP) has become a key technology of communication. Our work has been a practical implemenation of different scenarios to show that VoIP voice quality can be improved by adopting certain Quality of Service(QoS) measures such as classification, marking or queuing. It has been discussed that different QoS metrics like delay, packet loss and jitter could affect the voice quality of VoIP. To reduce the negative affects, one option is to implement certain QoS mechanisms with some set of configurations. For this purpose, Cisco IP phones have been configured in our topology with routers, switches, traffic generators, end stations and VoIP quality monitoring software called VQmanager. Tests have been divided into two sets. In one test a fixed bandwidth of 70 kbps is set while in the other test a random bandwidth is set with trafic generators unleashing packets of traffic. In both these tests further scenarios with configurations are worked out. They include no QoS, Auto Qos and Customized Qos mechanisms. Results have been indicative of top performance by the Customized QoS mechanism, in both sets of tests, followed by Auto QoS and no QoS mechanisms. It has been observed that a customized scenario could be a particular configuration to any organization’s needs and that will have the lowest delay, jitter and packet loss which are the main QoS metrics that impact the voice quality of VoIP. It can be fundamentally composed of classification of voice, data or web-traffic, marking and queuing depending upon the need of the organization. It is finally suggested to carry more tests in companies to get more data for analysis

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Cushnie, John. « QoS charging for Internet access networks : the wireless QoS gateway ». Thesis, Lancaster University, 2003. http://eprints.lancs.ac.uk/12300/.

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WANG, XIAODONG. « QoS ISSUES AND QoS CONSTRAINED DESIGN OF WIRELESS SENSOR NETWORKS ». University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1144634884.

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Jonsson, Björn. « Bluetooth QoS Scheduler ». Thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93114.

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Bluetooth is a low cost, short-range radio technology that enables electronic devices to communicate wirelessly via ad-hoc networks. Different kinds of applications may run over these networks, some of these applications with particular Quality of Service (QoS) requirements. One such application could for instance be an Audio application which need data frames to be delivered at regular interval to work properly. The communication over Bluetooth links is totally controlled by one of the participating nodes. Since this node controls the traffic and thereby controls the QoS within the network its communicating behaviour is of great importance for maintaining QoS reservations. A central part in maintaining QoS reservations is the scheduler, which prioritises between different tasks to be done such as which device that is allowed to transmit next. There is no standardised way to implement the Bluetooth scheduler. However, a Bluetooth scheduler should be able to handle QoS reservations, maintain fairness among the participating nodes, and utilise the available bandwidth efficiently. Furthermore a key requirement in Bluetooth is simplicity, therefore a Bluetooth scheduling algorithm should be of low complexity. This master thesis presents a new patented solution for an intra-piconet scheduling algorithm that is capable of maintaining QoS reservation, while being fair and also meet the low complexity requirement. This algorithm is presented in detail in the thesis and has been implemented in an ns2- based Bluetooth simulator. Simulations in this simulator are presented that verifies the scheduling algorithms functionality.
Bluetooth är en standard för trådlös ad-hoc kommunikation. Denna standard definierar i antalet noder begränsade nätverk (piconet) som kan kopplas samman till större nätverk (scatternet). Många olika typer av applikationer kan tänkas använda dessa nätverk, vissa av dessa med speciella krav på Quality of Service (QoS). Ett exempel så en dylik applikation är ljudöverföringar som kräver att data överförs med jämna mellanrum för att kunna fungera tillfredställande. Kommunikationen över ett Bluetooth-piconet kontrolleras helt av en av de deltagande enheterna. Eftersom denna enhet kontrollerar trafiken kontrollerar den också upprätthållandet av QoS reservationerna. En central del i detta upprätthållande är schemaläggaren, som är den del i en Bluetoothenhet som prioriterar mellan olika saker som ska utföras. Ett exempel på en sådan prioritering kan vara vilken enhet i nätverket som ska få kommunicera härnäst. Bluetooth standarden beskriver inte hur denna schemaläggare ska implementeras. Grundläggande krav på en Bluetooth schemaläggare är att den ska kunna hantera och upprätthålla QoS reservationer samtidigt som den delar den befintliga kapaciteten på ett rättvist och effektivt sätt mellan de deltagande enheterna. Vidare bör den ha en låg komplexitet eftersom enkelhet är ett krav på alla delar i ett Bluetoothsystem. Detta examensarbete presenterar en ny patenterad algoritm för schemaläggning i begränsade Bluetoothnät som är kapabel att upprätthålla QoS-reservationer, samtidigt som den distribuerar den tillgängliga kapaciteten på ett rättvist sätt. Algoritmen möter också upp till kravet på låg komplexitet. Rapporten innehåller vidare simuleringar av algoritmens funktion, dessa har utförts i en ns2-baserad Bluetooth miljö och verifierar algoritmens funktionalitet.

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Livres sur le sujet "QWs"

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Fītūrī, Muḥammad. Qaws al-layl, qaws al-nahār. al-Qāhirah : Dār al-Shurūq, 1994.

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Stiller, Burkhard, Michael Smirnow, Martin Karsten et Peter Reichl, dir. From QoS Provisioning to QoS Charging. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45859-x.

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Hanff, Helene. Q's legacy. London : Futura, 1986.

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Ḥusain, Faṿaz. Qaws quzaḥ. Ḥūrfaysh, Isrāʼīl : [s.n.], 2004.

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Hanff, Helene. Q's legacy. Thorndike, Me : Thorndike Press, 1985.

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Hanff, Helene. Q's Legacy. London : Deutsch, 1985.

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Hanff, Helene. Q's legacy. New York, N.Y : Penguin Books, 1986.

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Moore, C. A. QMS audit. London : HMSO, 1992.

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Hanff, Helene. Q's legacy. Boston : Little, Brown, 1985.

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Hanff, Helene. Q's legacy. Bath : Chivers, 1986.

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Chapitres de livres sur le sujet "QWs"

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Ghatak, Kamakhya Prasad. « The EP from QWs, NWs and QBs of HD Optoelectronic Materials ». Dans Springer Tracts in Modern Physics, 327–50. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11188-9_7.

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Zhang, Kelu, Shengwen Xie, Yu Zhang, Yingqiang Xu, Jinliang Wang et Zhichuan Niu. « GaSb-Based QWs 2 μm High Power Laser Diode ». Dans Advanced Functional Materials, 355–61. Singapore : Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0110-0_40.

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3

Glazov, M. M., et E. L. Ivchenko. « D’yakonov-Perel’s Spin Relaxation Under Electron-Electron Collisions in QWs ». Dans Optical Properties of 2D Systems with Interacting Electrons, 181–92. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0078-9_15.

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Gupta, Rita, N. Balkan et B. K. Ridley. « Hot Electron Instabilities in QWs : Acoustoelectric Effect and Two-Stream Plasma Instability ». Dans Negative Differential Resistance and Instabilities in 2-D Semiconductors, 127–39. Boston, MA : Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2822-7_8.

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Kochereshko, V. P., D. R. Yakovlev, R. A. Suris, G. V. Astakhov, W. Faschinger, W. Ossau, G. Landwehr, T. Wojtowicz, G. Karczewski et J. Kossut. « Combined Exciton-Electron Optical Processes in Optical Spectra of Modulation Doped QWs ». Dans Optical Properties of 2D Systems with Interacting Electrons, 125–36. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0078-9_10.

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Riechert, H., A. Yu Egorov, Gh Dumitras et B. Borchert. « Optical Properties of InGaAsN / GaAs QWs for long-wavelength lasers on GaAs ». Dans Springer Proceedings in Physics, 543–44. Berlin, Heidelberg : Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_256.

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Ghatak, Kamakhya Prasad. « The DRs in Quantum Wires (QWs) of Heavily Doped (HD) Non-parabolic Materials ». Dans Springer Tracts in Modern Physics, 209–41. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-21000-1_3.

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Ghatak, Kamakhya Prasad. « The EP from Quantum Wells (QWs) of Heavily Doped (HD) Non-parabolic Semiconductors ». Dans Springer Tracts in Modern Physics, 3–137. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11188-9_1.

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Suris, R. A. « Correlation Between Trion and Hole in Fermi Distribution in Process of Trion Photo-Excitation in Doped QWs ». Dans Optical Properties of 2D Systems with Interacting Electrons, 111–24. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0078-9_9.

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Janic, Milena, Fernando Kuipers, Xiaoming Zhou et Piet Van Mieghem. « Implications for QoS Provisioning Based on Traceroute Measurements ». Dans From QoS Provisioning to QoS Charging, 3–14. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45859-x_1.

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Actes de conférences sur le sujet "QWs"

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Gallacher, K., A. Ballabio, R. W. Millar, J. Frigerio, A. Bashir, I. MacLaren, Giovanni Isella, Michele Ortolani et Douglas J. Paul. « Intersubband absorption in p-Ge QWs on Si ». Dans 2016 IEEE 13th International Conference on Group IV Photonics (GFP). IEEE, 2016. http://dx.doi.org/10.1109/group4.2016.7739130.

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Ginzburg, Pavel, Alex Hayat et Meir Orenstein. « Nonlinear Optics in QWs with Tunable Local Phasematching ». Dans Nonlinear Optics : Materials, Fundamentals and Applications. Washington, D.C. : OSA, 2007. http://dx.doi.org/10.1364/nlo.2007.we9.

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Kane, Michael J., et Norman Apsley. « Surface Plasmon Enhanced Intersubband Resonance In AlGaAs QWs ». Dans 1987 Symposium on the Technologies for Optoelectronics, sous la direction de Alfred R. Adams. SPIE, 1988. http://dx.doi.org/10.1117/12.943412.

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Golz, Christian, Shabnam Dadgostar, W. Ted Masselink et Fariba Hatami. « Room temperature green to red electroluminescence from (Al,Ga)As/GaP QDs and QWs ». Dans SPIE OPTO, sous la direction de Heonsu Jeon, Li-Wei Tu, Michael R. Krames et Martin Strassburg. SPIE, 2016. http://dx.doi.org/10.1117/12.2213382.

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Möller, C., C. Berger, C. Fuchs, A. Ruiz Perez, S. W. Koch, J. Hader, J. V. Moloney et W. Stolz. « 1.2μm emitting VECSEL based on type-II aligned QWs ». Dans SPIE LASE, sous la direction de Keith G. Wilcox. SPIE, 2016. http://dx.doi.org/10.1117/12.2212438.

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Zeng, JiNan, Yongfeng Lu et Yasuo Oka. « Temperature effect for exciton dynamics in ZnCdSe/ZnSe QWs ». Dans Second International Symposium on Laser Precision Micromachining, sous la direction de Isamu Miyamoto, Yong Feng Lu, Koji Sugioka et Jan J. Dubowski. SPIE, 2002. http://dx.doi.org/10.1117/12.456856.

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Grinyaev, S. N., G. F. Karavaev, K. S. Zhuravlev et P. Tronc. « Novel IR Photodetectors Based on GaN/AlGaN HEMT with QWs or QDs in the Barrier ». Dans 2007 Siberian Conference on Control and Communications. IEEE, 2007. http://dx.doi.org/10.1109/sibcon.2007.371337.

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Zhuravlev, K. S., S. N. Grinyaev, G. F. Karavaev et P. Tronc. « New IR Photodetector Based on GaN QWs' or QDs' Located in Barrier of AlGaN/GaN Hemt Structure ». Dans 2007 17th International Crimean Conference - Microwave & Telecommunication Technology. IEEE, 2007. http://dx.doi.org/10.1109/crmico.2007.4368855.

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Bugge, F., G. Erbert, R. Hulsewede, P. Ressel, R. Staske, H. Wenzel, M. Weyers, U. Zeimer et G. Trankle. « High power 1120 nm-diode lasers with highly strained InGaAs QWs ». Dans CLEO 2001. Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Technical Digest. IEEE, 2001. http://dx.doi.org/10.1109/cleo.2001.947427.

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Kochereshko, V. « Excitons and Trions in Heavily Doped QWs at High Magnetic Fields ». Dans PHYSICS OF SEMICONDUCTORS : 27th International Conference on the Physics of Semiconductors - ICPS-27. AIP, 2005. http://dx.doi.org/10.1063/1.1994439.

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Rapports d'organisations sur le sujet "QWs"

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Muller, Richard P. Sandia QIS Capabilities. Office of Scientific and Technical Information (OSTI), juillet 2017. http://dx.doi.org/10.2172/1374031.

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Campbell, Andrew T., et Mischa Schwartz. Supporting QOS in Mobile Networks. Fort Belvoir, VA : Defense Technical Information Center, janvier 2002. http://dx.doi.org/10.21236/ada411151.

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Barbacci, Mario R., Robert Ellison, Anthony J. Lattanze, Judith A. Stafford et Charles B. Weinstock. Quality Attribute Workshops (QAWs) Third Edition. Fort Belvoir, VA : Defense Technical Information Center, août 2003. http://dx.doi.org/10.21236/ada418428.

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Apostolopoulos, G., S. Kama, D. Williams, R. Guerin, A. Orda et T. Przygienda. QoS Routing Mechanisms and OSPF Extensions. RFC Editor, août 1999. http://dx.doi.org/10.17487/rfc2676.

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Aranda, J. J., M. Cortes, J. Salvachúa, M. Narganes et I. Martínez-Sarriegui. The Quality for Service (Q4S) Protocol. RFC Editor, juillet 2020. http://dx.doi.org/10.17487/rfc8802.

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Carena, Marcella, et et al. QIS for Applied Quantum Field Theory. Office of Scientific and Technical Information (OSTI), mars 2020. http://dx.doi.org/10.2172/1606412.

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Benmerrouche, Mo. 07-BM QAS Beamline Radiation Shielding Analysis. Office of Scientific and Technical Information (OSTI), août 2017. http://dx.doi.org/10.2172/1493176.

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Snir, Y., Y. Ramberg, J. Strassner, R. Cohen et B. Moore. Policy Quality of Service (QoS) Information Model. RFC Editor, novembre 2003. http://dx.doi.org/10.17487/rfc3644.

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Huston, G. Next Steps for the IP QoS Architecture. RFC Editor, novembre 2000. http://dx.doi.org/10.17487/rfc2990.

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Reiersen, W., P. Heitzenroeder, G. Neilson, B. Nelson, M. Zarnstorff, T. Brown, M. Cole et al. Progress In NCSX and QPS Design and Construction. Office of Scientific and Technical Information (OSTI), octobre 2005. http://dx.doi.org/10.2172/899587.

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