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Molekuly v buněčných membránách / Molecules in Cell MembranesTimr, Štěpán January 2017 (has links)
Biological membranes are actively involved in a multitude of processes in living cells; therefore, a detailed characterization of their structure, dynamics, and function is essential for an understanding of living organisms at the molecular level. In this work, we made use of the high spatial and temporal resolution offered by computer simulations to investigate the behavior of several molecular species which associate with cellular membranes. Using a combination of classical molecular dynamics simulations and ab initio electronic structure calculations, we were able to characterize nonlinear optical properties of membrane- embedded fluorescent probes and thus contribute to establishing two-photon polarization microscopy as a tool of structural biology. Moreover, our molecular dynamics simulations provided an atomistic picture of the reversible membrane binding of recoverin, a neuronal calcium-sensing protein involved in vision adaptation, and they also yielded an important insight into the mechanism of its calcium-induced myristoyl switch. In addition, we examined the biological role of cholesterol oxidation and compared two methods of representing transmembrane voltage in molecular dynamics simulations.
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Die Entwicklung eines lichtgesteuerten Molekularschalters - ein Nanobauteil für den Einsatz in funktionellen Schaltkreisen und NanomaschinenSteller, Laura, Schulze, Renate, Habicher, Wolf D., Wolff, Thomas, Steiner, Gerald, Salzer, Reiner 29 August 2007 (has links)
Our target is the engineering of a light-gate molecular switch for the artificial ion channel, which will enable artificial ion channels to operate successfully in microfluidic systems, biomimetic sensors and various technical devices. A stable but reversible switch mechanism design is crucial, because the artificial ion channels known to date are lacking any control mechanism. Our artificial molecular switch is divided in two parts: the body part (calixarene) and a gate part based on light-responsive azo groups. The key to the controlling mechanism is the conformational change between cis and trans isomers, which is translated into movement of the gate. The gate is very robust and can either block or let the ions pass the molecular switch. Patch clamp investigations indicate successful integrations of gated artificial ion channels into lipid membranes. / Unser Ziel ist die Entwicklung eines lichtinduzierten Molekularschalters für künstliche Ionenkanäle, der als Nanobauteil für die Entwicklung von Sensoren in mikrofluiden Systemen, in biomimetischen Sensoren und in verschiedenen technischen Baugruppen eingesetzt werden soll. Für ein stabiles und zugleich reversibles System ist der Schaltmechanismus entscheidend, da die künstlichen Ionenkanäle bisher – soweit bekannt – keinen Regelmechanismus besitzen. Unser künstlicher molekularer Schalter setzt sich aus einem Rumpfteil (Calix[4]resorcinaren) und einer Schalteinheit, basierend auf lichtempfindlichen Azogruppen, zusammen. Die Schalteinheit ist sehr widerstandsfähig, kann den Ionenfluss blockieren oder die Ionen durch den Ionenkanal passieren lassen. Durch Bestrahlung wird die Kanalaktivität unterdrückt und reversibel wiederbelebt. Mittels Patch-Clamp-Untersuchungen wird das Schalten der synthetischen Ionenkanäle überprüft.
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Migration to P4-Programmable Switches and Implementation of the Rapid Spanning Tree Protocol / Övergång till P4-Programmerbara Switchar och Implementation av Rapid Spanning Tree ProtocolLindström, Henrik January 2020 (has links)
P4 is a high-level language for programming the data plane of a network switch. These P4-programmable switches come with no pre-defined behavior or protocols, so it is entirely up to the loaded P4 program to define these. This allows the user to exclude any unwanted functionality and to create custom protocols. It also removes the dependence on the switch vendor in terms of both trust and addition of new features. This thesis looks at migration from traditional switches to P4-programmable ones. Since no behavior is included out-of-the-box in the P4 switches, a search is made for open-source P4 projects and the functionality they provide is evaluated. It is found that most link layer functionality can be achieved with them, with the exception being loop prevention by spanning tree protocols. Therefore, one of the projects is extended with an implementation of the Rapid Spanning Tree Protocol based on the IEEE 802.1D-2004 standard. Finally, partial migration of networks to P4 switches and to the Software Defined Networking (SDN) paradigm is studied based on a literature review. Four general approaches and specific architectures for these are found, and it is concluded that such a hybrid network can still benefit from P4 and having a centralized SDN controller.
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Bankbyte och dess förväntningar : en kvantitativ studie om bankkunders förväntningar vid ett bankbyteStare, Filippa, Persson, Pontus January 2020 (has links)
Syftet med studien är att undersöka hur kundernas förväntningar på användarvänlighet på bankers produktutbud och förväntningar på byteskostnader har påverkats av ett bankbyte eller komplettering av en bank till. Det är av vikt för banker att förstå kunders förväntningar då kundrörligheten har ökat de senaste åren, därav är det fler kunder som genomgår bankbyte eller kompletterar med en bank till. Därmed har det blivit alltmer viktigt för bankerna att differentiera sig med sitt produktutbud och den aspekt som tas upp i studien vilket är användarvänlighet. Vidare associerar många kunder ett bankbyte med byteskostnader vilket gör att det är av intresse att förstå om de ändras efter ett bankbyte jämfört med ett tidigare bankbyte. Studien stadgat sig på tidigare forskning som har utgjort grunden för undersökningen, däremot uppmärksammades det ingen modell som mäter förväntningar på det sätt som studien avser att göra. Det har gjort att studien har utgått från uppfattad användarvänligheten i Teknologi acceptans modellen och Byteskostnader för att besvara studiens frågeställningar. Då studien har försökt dra generella slutsatser har det använts en kvantitativ enkät som utgjorde grunden för statistiska tester. Däremot är det viktigt att påpeka studiens generaliserbarhet då studien inte lyckades uppnå ett urval som kan representera alla svenska bankkunder. De resultat som studien fick fram visar att kunders förväntningar på användarvänlighet på bankers produktutbud inte har realiserats efter bankbytet eller kompletteringen. Det kunde inte heller påvisa någon skillnad på hur kunders förväntningar på byteskostnader har ändrats efter bankbytet eller kompletteringen. / The purpose of this study is examined how customer expectations on perceived ease of use of the supply of banks products and the expectations on switch cost is affected by a switch or to complement with one bank more. It´s important for banks to understand the customer´s expectations due to the overall increase in customer mobility, where more customers undergo a switch or to complement with one bank more. Therefor it is importance for banks to differentiate their perceived ease of use of the supply of products with is the aspect with is addressed in this study. Furthermore, many customers associate a bank switch with switching costs and therefore it´s a subject that that is important to understand if the expectation have changed after they undergo a switch. This study foundation is based on previous research however it´s have not been found a model how to the measure the expectations in the manner that this study attempt to do. Instead this study has used perceived ease of use from the Technology acceptance model and the theories of switching cost to answer these study questions. Because this study has tried to draw general assumptions from the result, it has been used a quantitative survey as a base for statistical tests. Therefor it´s important to acknowledge the generalizability in the study have failed to generate a sample with can represent the Swedish bank customers. However, the resultant in the study indicates that customers’ expectations regarding customer perceived ease of use of the supply of products have not been fulfilled after a switch of bank or to complement with one bank more. It could neither detect any difference in expectations of switching cost after a switch or to complement with one bank more.
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Influence of Switches and Crossings on Wheel Wear of a Freight VehicleDoulgerakis, Emmanouil January 2013 (has links)
Turnouts (Switches & Crossings) are important components in railway networks, as they provide the necessary flexibility for train operations by allowing trains to change among the tracks. But the turnout’s geometry with discontinuity in rail profiles and lack of transition curve causes additional wear both on track and on vehicle. The main goal of this MSc thesis is to investigate the influence of turnouts on wheel wear of a freight vehicle. This will be obtained by simulations in the commercial MBS software GENSYS. The wheel-rail contact is modelled according to Hertz’s theory and Kalker’s simplified theory, with the FASTSIM algorithm, and the wear calculations are performed according to Archard’s law. Wheel wear is estimated by considering variations in parameters which have effect on wheel-rail contact. All these variations are common in daily rail operation, and they are caused by it, i.e. worn wheel profiles, worn crossing nose and different stiffness of the stock and the switch rails at the beginning of the turnout. Moreover, the wheel wear is calculated for both possible directions which a vehicle can run, the diverging and the straight direction of the turnout. Especially for the straight direction, various running speeds have been tested as the speed limit when the vehicle follows the straight direction is higher than for the diverging part. Running with worn wheel profiles has the greatest impact in terms of increasing the wheel wear, especially on the outer part of wheel tread. In addition, the worn crossing nose results in increased wheel wear in this area. The results of the simulations concerning the different stiffness showed that the wheel wear caused by the contact of wheel and stock rail increases whereas the wear caused by the contact with the switch rail is kept at about the same level or decreases. It is concluded that turnouts have a significant impact on wheel wear, mainly because of the discontinuity in rail geometry and all the investigated parameters increase this impact. Moreover, great differences in wear values for areas close to each other are observed, mainly because of the wear coefficient values chosen in Archard’s wear map.
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Dedicated Hardware Context-Switch Services for Real-Time Multiprocessor SystemsAllard, Yannick 07 November 2017 (has links) (PDF)
Computers are widely present in our daily life and are used in critical applic-ations like cars, planes, pacemakers. Those real-time systems are nowadaysbased on processors which have an increasing complexity and have specifichardware services designed to reduce task preemption and migration over-heads. However using those services can add unpredictable overheads whenthe system has to switch from one task to another in some cases.This document screens existing solutions used in commonly availableprocessors to ease preemption and migration to highlight their strengths andweaknesses. A new hardware service is proposed to speed up task switchingat the L1 cache level, to reduce context switch overheads and to improvesystem predictability.The solution presented is based on stacking several identical cachememories at the L1 level. Each layer is able to save and restore its completestate independently to/from the main memory. One layer can be used forthe active task running on the processor while another layers can be restoredor saved concurrently. The active task can remain in execution until thepreempting task is ready in another layer after restoration from the mainmemory. The context switch between tasks can then be performed in avery short time by switching to the other layer which is now ready to runthe preempting task. Furthermore, the task will be resumed with the exactL1 cache memory state as saved earlier after the previous preemption. Theprevious task state can be sent back to the main memory for future use.Using this mechanism can lead to minimise the time required for migrationsand preemptions and consequently lower overheads and limit cache missesdue to preemptions and usually considered in the cache migration andpreemption delays. Isolation between tasks is also provided as they areexecuted from a dedicated layer.Both uniprocessor and multiprocessor designs are presented along withimplications on the real-time theory induced by the use of this hardware ser-vice. An implementation of the system is characterized and results show im-provements to the maximum and average execution time of a set of varioustasks: When the same size is used for the baseline cache and HwCS layers,94% of the tasks have a better execution time (up to 67%) and 80% have a bet-ter Worst Case Execution Time (WCET). 80% of the tasks are more predictableand the remaining 20% still have a better execution time. When we split thebaseline cache size among layers of the HwCS, measurements show that 75%of the tasks have a better execution time (up to 67%) leading to 50% of thetasks having a better WCET. Only 6% of the tasks suffer from worse executiontime and worse predictability while 75% of the tasks remain more predictablewhen using the HwCS compared to the baseline cache. / Les ordinateurs ont envahi notre quotidien et sont de plus en plus souventutilisés pour remplir des missions critiques. Ces systèmes temps réel sontbasés sur des processeurs dont la complexité augmente sans cesse. Des ser-vices matériels spécifiques permettent de réduire les coûts de préemption etmigration. Malheureusement, ces services ajoutent des temps morts lorsquele système doit passer d’une tâche à une autre.Ce document expose les solutions actuelles utilisées dans les processeurscourants pour mettre en lumière leurs qualités et défauts. Un nouveau ser-vice matériel (HwCS) est proposé afin d’accélérer le changement de tâches aupremier niveau de mémoire (L1) et de réduire ainsi les temps morts dus auxchangements de contextes tout en améliorant la prédictibilité du système.Bien que cette thèse se concentre sur le cache L1, le concept développépeut également s’appliquer aux autres niveaux de mémoire ainsi qu’àtout bloc dépendant du contexte. La solution présentée se base sur unempilement de caches identiques au premier niveau. Chaque couche del’empilement est capable de sauvegarder ou recharger son état vers/depuisla mémoire principale du système en toute autonomie. Une couche peutêtre utilisée par la tâche active pendant qu’une autre peut sauvegarder ourestaurer l’état d’une autre tâche. La tâche active peut ainsi poursuivre sonexécution en attendant que la tâche suivante soit rechargée. Le changementde contexte entre la tâche active et la tâche suivante peut alors avoir lieu enun temps très court. De plus, la tâche reprendra son exécution sur un cacheL1 dont l’état sera identique à celui au moment où elle a été interrompueprécédemment. L’état du cache de la tâche désormais inactive peut êtresauvegardé dans la mémoire principale en vue d’une utilisation ultérieure.Ce mécanisme permet de réduire au strict minimum le temps de calculperdu à cause des préemptions et migrations, les temps de sauvegarde et derechargement de la L1 n’ayant plus d’influence sur l’exécution des tâches. Deplus, chaque niveau étant dédié à une tâche, les interférences entre tâchessont réduites.Les propriétés ainsi que les implications sur les aspects temps réelsthéoriques sont présentées pour des systèmes mono et multiprocesseurs.Une implémentation d’un système uniprocesseur incluant ce servicematériel et sa caractérisation par rapport à l’exécution d’un set de tâchessont également présentées ainsi que les bénéfices apportés par le HwCS:Lorsque les couches du HwCS ont la même taille que le cache de base, 94%des tâches ont un meilleur temps d’exécution (jusqu’à 67%) et 80% ont unmeilleur pire temps d’exécution (WCET). 80% des tâches deviennent plusprédictibles et les 20% restants bénéficient néanmoins d’un meilleur WCET.Toutefois, si la taille du cache est partagée entre les couches du HwCS, lesmesures montrent que 75% des tâches ont un meilleur temps d’exécution,impliquant un meilleur WCET pour la moitié des tâches du système. Seule-ment 6% des tâches voient leur WCET augmenter et leur prédictibilitédiminuer tandis que 75% des tâches améliorent leur prédictibilité grâce auHwCS. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished
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Complexes de ruthénium (II) intégrant l'unité photochromique Diméthyldihydropyrène : Vers de nouvelles photo-réactivités / Ruthenium (II) complexes with dimethyldihydropyrene photochromic unit : Towards new photo-reactivitiesJacquet, Margot 07 December 2017 (has links)
Le travail présenté dans ce mémoire est dédié à l'élaboration de complexes de ruthénium(II) photo-commutables originaux incorporant le couple photochrome Diméthyldihydropyrène (DHP) / Cyclophanediène (CPD), pour de futurs dispositifs moléculaires optoélectroniques.Dans le but de réaliser des systèmes complexes pouvant reproduire les fonctions d'un circuit logique, une stratégie intéressante repose sur l'association de molécules photo-commutables et de complexes métalliques. Cependant, cette stratégie se confronte à certains obstacles majeurs, généralement associés à la perte des propriétés de commutation des photochromes organiques. En réponse aux précédents résultats confirmant cette tendance, deux nouvelles familles de complexes terpyridiniques de ruthénium(II) à base de DHP ont été synthétisées. Sachant que la présence de fonction pyridinium améliore significativement les propriétés d'isomérisation du cœur DHP, les centres métalliques ont été connectés soit via un lien benzyle pyridinium (Ru-Lpy+tpy) soit via un lien aryle pyridinium (Ru-LZincke). Bien que fonctionnant à plus faible énergie, le complexe Ru-LZincke présente des performances amoindries, en revanche les complexes Ru-Lpy+tpy affichent une préservation notable de leurs propriétés de commutation. Suite à la découverte d'une photo-réactivité originale favorisée par la présence du centre métallique, une famille analogue à base de complexes bipyridiniques de ruthénium(II) (Ru-Lpy+bpy) a été étudiée. Même si les mécanismes ne sont pas complètement rationalisés, les complexes Ru-Lpy+bpy se sont révélés être de remarquables candidats pour la réalisation de photo-commutateurs réversibles quantitativement dans le domaine du visible. / The work of this thesis is devoted to the development of original photo-switchable ruthenium(II) complexes incorporating the photochromic Dimethyldihydropyrene (DHP) / Cyclophanediene (CPD), for future optoelectronic molecular devices.In order to realize complex systems capable of reproducing the functions of a logic circuit, an interesting strategy is based on the association of photo-switchable molecules and metal complexes. However, this strategy is confronted with some major obstacles, generally associated with the loss of the switching properties of organic photochromes. In response to previous results confirming this trend, two new families of DHP-based terpyridine ruthenium(II) complexes have been synthesized. Since the presence of pyridinium function significantly improves the isomerization properties of the DHP core, the metal centers were connected either via a pyridinium benzyl linkage (Ru-Lpy+tpy) or via an aryl pyridinium linkage (Ru-LZincke). Although operating at lower energy, Ru-LZincke complex exhibits lessened performance, whereas Ru-Lpy+tpy complexes exhibit a notable preservation of their switching properties. Following the discovery of an original photo-reactivity favored by the presence of metal center, an analogue family based on ruthenium (II) bipyridine complexes (Ru-Lpy+bpy) was studied. Even if the mechanisms are not completely rationalized, Ru-Lpy+bpy complexes have proved to be remarkable candidates for the realization of quantitatively reversible photo-switches in the visible domain.
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Mitochondrial function provides instructive signals for activation-induced B cell fates / ミトコンドリアによる活性化B細胞運命決定機構の解析Jang, Kyoung-Jin 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18899号 / 医博第4010号 / 新制||医||1009(附属図書館) / 31850 / 京都大学大学院医学研究科医学専攻 / (主査)教授 生田 宏一, 教授 三森 経世, 教授 岩井 一宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Vanadium Dioxide Based Radio Frequency Tunable DevicesPan, Kuan-Chang January 2018 (has links)
No description available.
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Device Simulation and Analytical Modeling of Weak Harmonic Distortion in Bulk Silicon Radio Frequency MOSFET SwitchesNiemeier, Dennis 13 April 2021 (has links)
Diese Dissertation behandelt schwache Nichtlinearitäten in Radiofrequenzschaltern, die auf Grundlage von CMOS-Transistoren realisiert werden. Der besondere Schwerpunkt liegt auf der analytischen Modellierung sowie der Simulation der Nichtlinearität mithilfe einer TCAD (Technology Computer-Aided Design) Software.
Die Nichtlinearität kann nach den verschiedenen Quellen klassifiziert werden: der Transistornichtlinearität und der Substratnichtlinearität. Für beide Bereiche werden umfassende Simulationen und analytische Modellierungen sowie Messungen präsentiert und interpretiert. / This dissertation treats weak nonlinearities in radio frequency switches that are realised based on CMOS transistor technology. A special focus lies on the analytical modeling and TCAD simulation of the nonlinearity.
The nonlinearity is sorted into substrate and transistor nonlinearity. For both nonlinear regions profound simulations, analytical modeling and measurements are presented and interpreted.
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