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1
Feng, Junyi. « Device-to-Device Communications in LTE-Advanced Network ». Télécom Bretagne, 2013. http://www.telecom-bretagne.eu/publications/publication.php?idpublication=14215.
Texte intégralRésumé :
La communication device-to-device (D2D) est un nouvel aspect prometteur dans les réseaux LTE-Advanced. Elle est mise en place pour permettre une détection efficace et une communication de proximité entre mobiles. Grâce aux capacités D2D, les mobiles de proximité sont capables de se détecter entre eux en utilisant la technologie radio LTE et de communiquer entre eux via un lien direct. Cette thèse porte sur la conception, la coordination et les tests d'un réseau hybride avec la technologie D2D et les communications cellulaires. Les exigences de conception et les choix des fonctions dans la couche physique et MAC qui permettent la détection D2D et la communication reposant sur les réseaux LTE sont analysés. De plus, une stratégie de planification centralisée dans la station de base est proposée afin de coordonner les communications de données D2D en liaison descendante pour le réseau LTE FDD. Cette stratégie de planification combine de multiple techniques telles que le mode de sélection, l'allocation des ressources et d'énergie, afin d'améliorer les performances des utilisateurs dans une cellule. Enfin, les performances des communications de données D2D reposant sur le système LTE sont mesurées à partir d'un simulateur, au niveau système, avec un scénario comportant de multiples liens de communicationDevice-to-device (D2D) communication is a promising new feature in LTE-Advanced networks. It is brought up to enable efficient discovery and communication between proximate devices. With D2D capability, devices in physical proximity could be able to discover each other using LTE radio technology and to communicate with each other via a direct data path. This thesis is concerned with the design, coordination and testing of a hybrid D2D and cellular network. Design requirements and choices in physical and MAC layer functions to support D2D discovery and communication underlaying LTE networks are analyzed. In addition, a centralized scheduling strategy in base station is proposed to coordinate D2D data communication operating in LTE spectrum. The scheduling strategy combines multiple techniques, including mode selection, resource and power allocation, to jointly achieve an overall user performance improvement in a cell. Finally the performances of D2D data communication underlaying LTE system are calibrated in a multi-link scenario via system-level simulation
2
Wu, Yue. « Advanced technologies for device-to-device communications underlaying cellular networks ». Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15391/.
Texte intégralRésumé :
The past few years have seen a major change in cellular networks, as explosive growth in data demands requires more and more network capacity and backhaul capability. New wireless technologies have been proposed to tackle these challenges. One of the emerging technologies is device-to-device (D2D) communications. It enables two cellular user equipment (UEs) in proximity to communicate with each other directly reusing cellular radio resources. In this case, D2D is able to offload data traffic from central base stations (BSs) and significantly improve the spectrum efficiency of a cellular network, and thus is one of the key technologies for the next generation cellular systems. Radio resource management (RRM) for D2D communications and how to effectively exploit the potential benefits of D2D are two paramount challenges to D2D communications underlaying cellular networks. In this thesis, we focus on four problems related to these two challenges. In Chapter 2, we utilise the mixed integer non-linear programming (MINLP) to model and solve the RRM optimisation problems for D2D communications. Firstly we consider the RRM optimisation problem for D2D communications underlaying the single carrier frequency division multiple access (SC-FDMA) system and devise a heuristic sub-optimal solution to it. Then we propose an optimised RRM mechanism for multi-hop D2D communications with network coding (NC). NC has been proven as an efficient technique to improve the throughput of ad-hoc networks and thus we apply it to multi-hop D2D communications. We devise an optimal solution to the RRM optimisation problem for multi-hop D2D communications with NC. In Chapter 3, we investigate how the location of the D2D transmitter in a cell may affect the RRM mechanism and the performance of D2D communications. We propose two optimised location-based RRM mechanisms for D2D, which maximise the throughput and the energy efficiency of D2D, respectively. We show that, by considering the location information of the D2D transmitter, the MINLP problem of RRM for D2D communications can be transformed into a convex optimisation problem, which can be efficiently solved by the method of Lagrangian multipliers. In Chapter 4, we propose a D2D-based P2P le sharing system, which is called Iunius. The Iunius system features: 1) a wireless P2P protocol based on Bittorrent protocol in the application layer; 2) a simple centralised routing mechanism for multi-hop D2D communications; 3) an interference cancellation technique for conventional cellular (CC) uplink communications; and 4) a radio resource management scheme to mitigate the interference between CC and D2D communications that share the cellular uplink radio resources while maximising the throughput of D2D communications. We show that with the properly designed application layer protocol and the optimised RRM for D2D communications, Iunius can significantly improve the quality of experience (QoE) of users and offload local traffic from the base station. In Chapter 5, we combine LTE-unlicensed with D2D communications. We utilise LTE-unlicensed to enable the operation of D2D in unlicensed bands. We show that not only can this improve the throughput of D2D communications, but also allow D2D to work in the cell central area, which normally regarded as a “forbidden area” for D2D in existing works. We achieve these results mainly through numerical optimisation and simulations. We utilise a wide range of numerical optimisation theories in our works. Instead of utilising the general numerical optimisation algorithms to solve the optimisation problems, we modify them to be suitable for the specific problems, thereby reducing the computational complexity. Finally, we evaluate our proposed algorithms and systems through sophisticated numerical simulations. We have developed a complete system-level simulation framework for D2D communications and we open-source it in Github: https://github.com/mathwuyue/py- wireless-sys-sim.
3
Lin, Meifang. « Robust organic light emitting device with advanced functional materials and novel device structures ». HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/939.
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Hadimani, Ravi L. « Advanced magnetoelastic and magnetocaloric materials for device applications ». Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54960/.
Texte intégralRésumé :
Magnetocaloric and magnetoelastic materials can be utilised in various device applications and have a potential to increase their efficiency by a considerable amount. In this thesis, Gd5(SixGei_x)4 is extensively researched on its magnetic properties such as magnetic phase transition temperature, magnetostriction, magnetoresistance and anisotropy. Field induced phase transition in Gd5(SixGei_x)4 was observed in several compositions and the rate of change of the first order phase transition temperature was determined to be approximately 5 K/Tesla. Various methods of transition temperature measurements were compared and the Arrott plot technique was determined to be accurate method for magnetocaloric materials. An advanced technique based on Arrott plots was developed to estimate the second order phase transition temperature when it is suppressed by the first order phase transition. This technique was also extended to estimate the transition temperature of mixed phase alloys. Field induced phase transition at high temperature using high magnetic field measurements up to 9 Tesla were carried out on two compositions of Gd5(SixGei-x)4 for x=0.5 and x=0.475 to validate the Arrott plot technique. Magnetostriction measurements were carried out on Gd5(SixGei_x)4 for various compositions. Fine structure was observed in the magnetostriction measurement in single crystal and polycrystalline Gd5Si1.95Ge2.05 samples but not on other compositions, which might be due to the presence of a secondary phase. It was demonstrated that a giant magnetostriction of the order of 1813 ppm could be obtained by varying the temperature using a Peltier cell and removing the requirement of bulky equipment such as Physical Properties Measurement System (PPMS). Magnetoresistance was measured for various compositions and an irreversible increase in resistivity was observed which depended linearly on the number of thermal cycles passing through the first order phase transition temperature. The irreversibly increased resistivity was recovered by holding the samples at high temperature for a long period of time of up to 3 days. A theoretical model was developed to explain the recovery in the resistance and was experimentally verified. First order magnetocrystalline anisotropy constant Kj, easy and hard axes of the single crystal Gd5Si2.7Gei j sample were determined using magnetic moment as a function of angle of rotation of the sample at room temperature. Dependence of the first order phase transition temperature on the angle of rotation of the single crystal Gd5Si2Ge2 sample was determined to be negligible. Additionally polycrystalline samples of Gd5Sii.8Ge2.2 and Gd5Sii.9Ge2.i were prepared by arc- melting and heat treatment was carried out on these samples in accordance with the literature to remove residual secondary phases in the sample at the Materials and Metallurgy Department of the Birmingham University. XRD measurements were carried out on these samples to confirm the crystal structure.
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Rickard, Jonathan James Stanley. « Advanced micro-engineered platforms for novel device technologies ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8303/.
Texte intégralRésumé :
The objectives of this thesis are to explore, design, fabricate and implement the use of advanced micro-engineered platforms to be exploited as versatile, novel device technologies. An increasing number of technologies require the fabrication of conductive structures on a broad range of scales and large areas. Here, we introduce advanced yet simple electrohydrodynamic lithography for patterning conductive polymers directly on a substrate with high-fidelity. We illustrate the generality of this robust, low-cost method by structuring thin films via electric-field-induced instabilities, yielding well-defined conductive structures with a broad range of feature sizes. We show the feasibility of the polypyrrole-based structures for field-effect transistors, which might herald a route towards submicron device applications. We also demonstrate a miniaturised platform technology for timely, sensitive and rapid point-of-care diagnostics of disease-indicative biomarkers. Our micro-engineered device technology (MEDTech) is based on reproducible electrohydrodynamically fabricated platforms for surface enhanced Raman scattering enabling tuneable, high-throughput nanostructures yielding high-signal enhancements. These, integrated within a microfluidic-chip provide cost-effective, portable devices for detection of miniscule biomarker concentrations from biofluids, offering clinical tests that are simple, rapid and minimally invasive. Using MEDTech to analyse clinical blood-plasma, we deliver a prognostic tool for long-term outcomes, in the hospital or at the point-of-care.
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Wu, Dongping. « Novel concepts for advanced CMOS : Materials, process and device architecture ». Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3805.
Texte intégralRésumé :
The continuous and aggressive dimensional miniaturization ofthe conventional complementary-metal-oxide semiconductor (CMOS)architecture has been the main impetus for the vast growth ofIC industry over the past decades. As the CMOS downscalingapproaches the fundamental limits, unconventional materials andnovel device architectures are required in order to guaranteethe ultimate scaling in device dimensions and maintain theperformance gain expected from the scaling. This thesisinvestigates both unconventional materials for the gate stackand the channel and a novel notched-gate device architecture,with the emphasis on the challenging issues in processintegration.
High-κ gate dielectrics will become indispensable forCMOS technology beyond the 65-nm technology node in order toachieve a small equivalent oxide thickness (EOT) whilemaintaining a low gate leakage current. HfO2and Al2O3as well as their mixtures are investigated assubstitutes for the traditionally used SiO2in our MOS transistors. These high-κ filmsare deposited by means of atomic layer deposition (ALD) for anexcellent control of film composition, thickness, uniformityand conformality. Surface treatments prior to ALD are found tohave a crucial influence on the growth of the high-κdielectrics and the performance of the resultant transistors.Alternative gate materials such as TiN and poly-SiGe are alsostudied. The challenging issues encountered in processintegration of the TiN or poly-SiGe with the high-k are furtherelaborated. Transistors with TiN or poly-SiGe/high-k gate stackare successfully fabricated and characterized. Furthermore,proof-of-concept strained-SiGe surface-channel pMOSFETs withALD high-κ dielectrics are demonstrated. The pMOSFETs witha strained SiGe channel exhibit a higher hole mobility than theuniversal hole mobility in Si. A new procedure for extractionof carrier mobility in the presence of a high density ofinterface states found in MOSFETs with high-κ dielectricsis developed.
A notched-gate architecture aiming at reducing the parasiticcapacitance of a MOSFET is studied. The notched gate is usuallyreferred to as a local thickness increase of the gatedielectric at the feet of the gate above the source/drainextensions. Two-dimensional simulations are carried out toinvestigate the influence of the notched gate on the static anddynamic characteristics of MOSFETs. MOSFETs with optimizednotch profile exhibit a substantial enhancement in the dynamiccharacteristics with a negligible effect on the staticcharacteristics. Notched-gate MOSFETs are also experimentallyimplemented with the integration of a high-κ gatedielectric and a poly-SiGe/TiN bi-layer gate electrode.
Key words:CMOS technology, MOSFET, high-κ, gatedielectric, ALD, surface pre-treatment, metal gate, poly-SiGe,strained SiGe, surface-channel, buried-channel, notchedgate.
7
Chang, Ruey-dar. « Physics and modeling of dopant diffusion for advanced device applications / ». Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Xu, Zhenxue. « Advanced Semiconductor Device and Topology for High Power Current Source Converter ». Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11068.
Texte intégralRésumé :
This dissertation presents the analysis and development of an innovative semiconductor device and topology for the high power current source converter (CSC).
The CSC is very attractive in high power applications due to its lower output dv/dt, easy regeneration capability and implicit short-circuit protection. Traditionally, either a symmetrical gate turn-off (GTO) thyritor or an asymmetrical GTO in series with a diode is used as the power switch in the CSC. Since the GTO has a lower switching speed and requires a complicated gate driver, the symmetrical GTO based CSC usually has low dynamic response speed and low efficiency. To achieve high power rating, fast dynamic response speed and low harmonics, an advanced semiconductor device and topology are needed for the CSC.
Based on symmetrical GTO and power MOSFET technologies, a symmetrical emitter turn-off (ETO) thyristor is developed that shows superior switching performance, high power rating and reverse voltage blocking capability. The on-state characteristics, forced turn-on characteristics, forced turn-off characteristics and the load-commutated characteristics are studied. Test results show that although the load-commutation loss is high, the developed symmetrical ETO is suitable for use in high power CSC due to its low conduction loss, fast switching speed and reverse voltage blocking capability.
The snubberless turn-on capability is preferred for a semiconductor device in a power conversion system, and can be achieved for devices with forward biased safe operation area (FBSOA). The FBSOA of the ETO is investigated and experimentally demonstrated. The ETO device has excellent FBSOA due to the negative feedback provided by the emitter switch. However, the FBSOA for a large area ETO is poor. A new ETO concept is therefore proposed for future development in order to demonstrate the FBSOA over a large area device.
To improve the turn-on performance of the large area ETO, a novel concept, named the transistor-mode turn-on, is proposed and studied. During the transistor-mode turn-on process, the ETO behaves like a transistor instead of a thyristor. Without a snubber, the transistor-mode turn-on for the ETO is hard to achieve. Through the selection of a proper gate drive and di/dt snubber, the transistor-mode turn-on can be implemented, and the turn-on performance for the ETO can be dramatically improved.
To increase the power rating of the CSC without degrading the utilization of power semiconductor devices, a novel multilevel CSC, named the parallel-cell multilevel CSC, is proposed. Based on a six-switch CSC cell, the parallel-cell multilevel CSC has the advantages of high power rating, low harmonics, fast dynamic response and modularity. Therefore, it is very suitable for high power applications. The power stage design, modeling, control and switching modulation scheme for a parallel-cell multilevel CSC based static var compensator (STATCOM) are analyzed and verified through simulation.Ph. D.
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Wong, Chun Wai. « Device technology and baseband switch for the advanced on-board processing satellites ». Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/843454/.
Texte intégralRésumé :
This thesis examines a new market for satellite communication serving small fixed-station business systems. This market requires transmission between a large number of smaller and cheaper earth terminals. The traffic requirements for satellite business services in Europe by the year 2000 have been reviewed. An advanced regenerative on-board processing business satellite with 13 spot-beams for the European coverage was then proposed to meet the expected traffic growth. This satellite system is designed to meet the needs of the user rather than, as traditionally, the user fitting in with the satellite. SCPC/FDMA and R-TDMA (reservation-TDMA) multiple access schemes were found to be most suitable for the proposed system serving many small users whose traffic was mixed voice, data and video. The architecture of the satellite payload has been studied and two main functional blocks, transmultiplexer and baseband switch were identified. The use of the transmultiplexer is to transform the EDM channels into TDM and the baseband switch is to provide full connectivity between all the stations so that the revolutionary idea of having a "switchboard in the sky" can be realised. The development work for the baseband switch is reported in detail in this thesis together with a comparison of different architectures for the baseband switch. A proof-of-concept model for the baseband switch was designed, built and tested. From the test results, the feasibility of implementing the baseband switch using the chosen architecture was proved. Another main area studied in this thesis was device technology. The present and future capability of bipolar, CMOS and GaAs technology has been investigated concentrating mainly on digital devices and semi-custom technology. Since the satellite is operating in an hostile environment, it has been necessary to study the effects of radiation on semiconductor devices. The outcome of these studies indicate that it is very promising to launch such advanced satellite payloads in the late 1990's.
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Tanenbaum, Laura Melanie. « Design of an intraperitoneal drug-release device for advanced ovarian cancer therapy ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104610.
Texte intégralRésumé :
Thesis: Ph. D. in Medical Engineering and Medical Physics, Harvard-MIT Program in Health Sciences and Technology, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 111-121).
More than 14,000 women in the United States die from ovarian cancer each year. The standard of care is tumor-debulking surgery followed by adjuvant chemotherapy. Combination intraperitoneal (IP) and intravenous (IV) chemotherapy has been shown to lengthen survival over IV therapy alone. Large-volume infusions, drug-associated toxicity, and catheter-associated complications, however, increase morbidity and limit patient adherence, often resulting in discontinuation of IP therapy. The technical skill required for catheter implantation and IP chemotherapy administration has also limited its clinical adoption. The proposed solution is an implantable IP device capable of localized drug delivery that maintains the efficacy of the standard of care and overcomes current clinical challenges. A reservoir-based device was developed to release cisplatin at a constant rate. In vivo studies demonstrated that continuous dosing reduces tumor burden to the same extent as weekly IP injections. The implanted device induced significantly less systemic toxicity compared to IP injections, despite administration of higher cumulative doses. A subsequent in vitro study revealed that greater tumor shrinkage following continuous cisplatin exposure was achieved with smaller tumor nodules. These results support that an implanted device would be maximally effective against microscopic residual disease. In vitro results also illustrated that a human-scale device fabricated from orifice-lined silicone can be designed to release cisplatin continuously at the desired rate. The promising preclinical results in this thesis highlight the potential for this novel IP dosing regimen to improve the treatment of late-stage ovarian cancer and set the stage for development of the proposed human device.
by Laura Melanie Tanenbaum.
Ph. D. in Medical Engineering and Medical Physics
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Nath, Digbijoy N. « Advanced polarization engineering of III-nitride heterostructures towards high-speed device applications ». The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376927078.
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Luxmoore, Issac J. « Micro-electronic device fabrication using advanced focused ion beam and related techniques ». Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489138.
Texte intégralRésumé :
In order to rapidly prototype novel devices with nanoscale precision, new fabrication techniques which can provide high resolution and a quick tum-around are increasingly important in research and development. The focused ion beam (FIB) system is one such instrument and provides the user with the ability to both remove and deposit material with sub lOOnm accuracy without the need for a mask or resist. In this work, focused ion beam technology has been assessed as a technique for prototype microelectronic device fabrication in three main areas.
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Wang, Haihong. « Advanced transport models development for deep submicron low power CMOS device design / ». Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Scarpellini, M. « ADVANCED MATERIALS : PREPARATION, STUDY AND OPTIMIZATION OF THIN FILM FOR OPTO-ELECTRONIC DEVICE ». Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150151.
Texte intégralRésumé :
The term “optoelectronic devices” is by now used for devices in which both electrons and photons are essential for their operation, as a natural evolution from the definitions of electronic devices that involved only electrons and holes in their operation and of photonic devices that involved only photons in their operation. One of the new lighting technologies which emerged within the past two decades and has the potential of becoming more energy-efficient then the existing light sources, is the Solid State Lighting technology of Organic Light Emitting Diodes (OLEDs). In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting anode and metallic cathode. When an appropriate current is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). The first part of this PhD Thesis surveyed different aspect in OLED technology that are currently under debate. In particular chapter 2 is devoted to the study, preparation and optimization of thin films between the organic hole transport layer and the anode surface while chapter 3 deals with the synthesis of trifluorene compound, with methoxy substituents, as possible UV-blue emitter. The second part of this PhD work is dedicated to the synthesis and study of new materials with interesting emissive and second order NLO properties. In particular pyrene based chromophores are investigated in chapter 4, while chapter 5 deals with the synthesis of organic-inorganic perylene-POSS hybrids with enhanced emissive properties.
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Horikawa, Tsuyoshi. « A study of advanced integrated semiconductor device and process technologies for data storage and transmission ». 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215222.
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Zhang, Min [Verfasser]. « Organic Light Emitting Diodes : Electron Injection Layers for Advanced Solution Processed Device Architectures / Min Zhang ». Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1161801820/34.
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D'Esposito, Rosario. « Electro-thermal characterization, TCAD simulations and compact modeling of advanced SiGe HBTs at device and circuit level ». Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0147/document.
Texte intégralRésumé :
Ce travail de thèse présente une étude concernant la caractérisation des effets électrothermiques dans les transistors bipolaires à hétérojonction (HBT) en SiGe. Lors de ces travaux, deux procédés technologiques BiCMOS à l’état de l’art ont été analysés: le B11HFC de Infineon Technologies (130nm) et le B55 de STMicroelectronics (55nm).Des structures de test dédiées ont étés conçues, pour évaluer l’impact électrothermique du back end of line (BEOL) de composants ayant une architecture à un ou plusieurs doigts d’émetteur. Une caractérisation complète a été effectuée en régime continu et en mode alternatif en petit et en grand signal. De plus, une extraction des paramètres thermiques statiques et dynamiques a été réalisée et présentée pour les structures de test proposées. Il est démontré que les figures de mérite DC et RF s’améliorent sensiblement en positionnant des couches de métal sur le transistor, dessinées de manière innovante et ayant pour fonction de guider le flux thermique vers l’extérieur. L’impact thermique du BEOL a été modélisé et vérifié expérimentalement dans le domaine temporel et fréquentiel et aussi grâce à des simulations 3D par éléments finis. Il est à noter que l’effet du profil de dopage sur la conductivité thermique est analysé et pris en compte.Des topologies de transistor innovantes ont étés conçues, permettant une amélioration des spécifications de l’aire de sécurité de fonctionnement, grâce à un dessin innovant de la surface d’émetteur et du deep trench (DTI).Un modèle compact est proposé pour simuler les effets de couplage thermique en dynamique entre les émetteurs des HBT multi-doigts; ensuite le modèle est validé avec de mesures dédiées et des simulations TCAD.Des circuits de test ont étés conçus et mesurés, pour vérifier la précision des modèles compacts utilisés dans les simulateurs de circuits; de plus, l’impact du couplage thermique entre les transistors sur les performances des circuits a été évalué et modélisé. Finalement, l’impact du dissipateur thermique positionné sur le transistor a été étudié au niveau circuit, montrant un réel intérêt de cette approcheThis work is focused on the characterization of electro-thermal effects in advanced SiGe hetero-junction bipolar transistors (HBTs); two state of the art BiCMOS processes have been analyzed: the B11HFC from Infineon Technologies (130nm) and the B55 from STMicroelectronics (55nm).Special test structures have been designed, in order to evaluate the overall electro-thermal impact of the back end of line (BEOL) in single finger and multi-finger components. A complete DC and RF electrical characterization at small and large signal, as well as the extraction of the device static and dynamic thermal parameters are performed on the proposed test structures, showing a sensible improvement of the DC and RF figures of merit when metal dummies are added upon the transistor. The thermal impact of the BEOL has been modeled and experimentally verified in the time and frequency domain and by means of 3D TCAD simulations, in which the effect of the doping profile on the thermal conductivity is analyzed and taken into account.Innovative multi-finger transistor topologies are designed, which allow an improvement of the SOA specifications, thanks to a careful design of the drawn emitter area and of the deep trench isolation (DTI) enclosed area.A compact thermal model is proposed for taking into account the mutual thermal coupling between the emitter stripes of multi-finger HBTs in dynamic operation and is validated upon dedicated pulsed measurements and TCAD simulations.Specially designed circuit blocks have been realized and measured, in order to verify the accuracy of device compact models in electrical circuit simulators; moreover the impact on the circuit performances of mutual thermal coupling among neighboring transistors and the presence of BEOL metal dummies is evaluated and modeled
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Noor, Mumin. « Interaction of the left ventricle and left ventricular assist device during mechanical circulatory support for advanced heart failure ». Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/51108.
Texte intégralRésumé :
The work in this thesis was undertaken to examine clinically significant questions at a time of evolving Left Ventricular Assist Device (LVAD) technology. The main theme of the research was to increase our understanding of the interaction between left ventricle and newer continuous flow LVADs through both in-vitro models and clinical studies with the ultimate aim of improving patient care. The hydrodynamic performance of the two continuous flow LVADs (Thoratec HeartMate II and HeartWare HVAD) was compared in a normothermic, human blood-filled pulsatile mock circulation model under conditions of steady flow and under simulated physiological conditions. These experiments were repeated using dextrose in order to determine its suitability as a mock circulation blood analogue. This study found that clinically representative pulsatile relationships are better represented as H/Q loops instead of linear plots. This allows for greater understanding of the instantaneous H/Q relationship of LVADs with the native LV. The relationship between LVAD pump speed and exercise capacity was studied in patients receiving support from a continuous flow HM II and examined the influence of residual LV function on this relationship. This study found that exercise time and pkVO2 are sensitive to pump speed in patients with poor LV function receiving HM II support. By contrast, insensitivity of exercise parameters such as pkVO2 and exercise time to changes in pump speed may be a non-invasive indicator for LV functional recovery in patients receiving support with rotary LVADs. Effect of temporarily increasing pump speed on exercise capacity was then studied in a group of patients supported with continuous flow LVADs. The study showed that it was safe and feasible to temporarily increase LVAD speed during exercise and this resulted in a significant increase in peak oxygen consumption. Furthermore, improved exercise capacity was observed in both axial and centrifugal pump devices. Radial strain and radial strain rate values were measured by Speckle Tracking Echocardiography to assess LV function and mechanics. The effect of reducing pump speed on these measurements was also examined. My result showed that the radial strain values are significantly lower than normal range and in keeping with advanced heart failure patients. I found the measurements to be relatively independent of degree of LVAD speed and may potentially reflect underlying LV function. Lastly, I investigated the feasibility of recording acoustic waveforms from a LVAD using an electronic stethoscope and analysing the frequency components of the LVAD acoustic spectrum. After recording the findings in patients with normal pump function, we compared it to patients with pump thrombosis. The acoustic profile is primarily determined by rotation speed and device design. In pump thrombosis cases, there were atypical spectral peaks during pump thrombus episodes. Acoustic monitoring is a simple non-invasive method which may have clinical utility in the diagnosis of pump thrombus episodes in patients supported by a rotary LVAD.
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Amate, Ahmed Mohammed. « Device-device communication and multihop transmission for future cellular networks ». Thesis, University of Hertfordshire, 2015. http://hdl.handle.net/2299/16309.
Texte intégralRésumé :
The next generation wireless networks i.e. 5G aim to provide multi-Gbps data traffic, in order to satisfy the increasing demand for high-definition video, among other high data rate services, as well as the exponential growth in mobile subscribers. To achieve this dramatic increase in data rates, current research is focused on improving the capacity of current 4G network standards, based on Long Term Evolution (LTE), before radical changes are exploited which could include acquiring additional/new spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell edge users vulnerable to inter-cell interference. In addition, wireless transmission is commonly hindered by fading and pathloss. In this direction, this thesis focuses on improving the performance of cell edge users in LTE and LTE-Advanced (LTE-A) networks by initially implementing a new Coordinated Multi-Point (CoMP) algorithm to mitigate cell edge user interference. Subsequently Device-to-Device (D2D) communication is investigated as the enabling technology for maximising Resource Block (RB) utilisation in current 4G and emerging 5G networks. It is demonstrated that the application, as an extension to the above, of novel power control algorithms, to reduce the required D2D TX power, and multihop transmission for relaying D2D traffic, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond-the-state-of-the-art LTE system-level simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards. Additionally, a novel interference modelling scheme using the 'wrap around' technique was proposed and implemented that maintained the topology of flat surfaced maps, allowing for use with cell planning tools while obtaining accurate and timely results in the SLS compared to the few existing platforms. For the proposed CoMP algorithm, the adaptive beamforming technique was employed to reduce interference on the cell edge UEs by applying Coordinated Scheduling (CoSH) between cooperating cells. Simulation results show up to 2-fold improvement in terms of throughput, and also shows SINR gain for the cell edge UEs in the cooperating cells. Furthermore, D2D communication underlaying the LTE network (and future generation of wireless networks) was investigated. The technology exploits the proximity of users in a network to achieve higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the Evolved Node B (eNB) i.e. by direct communication between User Equipment (UE). Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for a D2D receiver, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNB in the network. The impact of interference from the simultaneous transmission however impedes the achievable data rates of cellular UEs in the network, especially at the cell edge. Thus, a power control algorithm was proposed to mitigate the impact of interference in the hybrid network (network consisting of both cellular and D2D UEs). It was implemented by setting a minimum SINR threshold so that the cellular UEs achieve a minimum performance, and equally a maximum SINR threshold to establish fairness for the D2D transmission as well. Simulation results show an increase in the cell edge throughput and notable improvement in the overall SINR distribution of UEs in the hybrid network. Additionally, multihop transmission for D2D UEs was investigated in the hybrid network: traditionally, the scheme is implemented to relay cellular traffic in a homogenous network. Contrary to most current studies where D2D UEs are employed to relay cellular traffic, the use of idle nodes to relay D2D traffic was implemented uniquely in this thesis. Simulation results show improvement in D2D receiver throughput with multihop transmission, which was significantly better than that of the same UEs performance with equivalent distance between the D2D pair when using single hop transmission.
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Sahoo, Amit Kumar. « Electro-thermal Characterizations, Compact Modeling and TCAD based Device Simulations of advanced SiGe : C BiCMOS HBTs and of nanometric CMOS FET ». Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14557/document.
Texte intégralRésumé :
Ce travail de thèse présente une évaluation approfondie des différentes techniques de mesure transitoire et dynamique pour l’évaluation du comportement électro-thermique des transistors bipolaires à hétérojonctions HBT SiGe:C de la technologie BiCMOS et des transistors Métal-Oxyde-Semiconducteur à effet de champ (MOSFET) de la technologie CMOS 45nm. En particulier, je propose une nouvelle approche pour caractériser avec précision le régime transitoire d'auto-échauffement, basée sur des mesures impulsionelles. La méthodologie a été vérifiée par des mesures statiques à différentes températures ambiantes, des mesures de paramètres S à basses fréquences et des simulations thermiques transitoires. Des simulations thermiques par éléments finis (TCAD) en trois dimensions ont été réalisées sur les transistors HBTs de la technologie submicroniques SiGe: C BiCMOS. Cette technologie est caractérisée par une fréquence de transition fT de 230 GHz et une fréquence maximum d’oscillation fMAX de 290 GHz. Par ailleurs, cette étude a été réalisée sur les différentes géométries de transistor. Une évaluation complète des mécanismes d'auto-échauffement dans les domaines temporels et fréquentiels a été réalisée. Une expression généralisée de l'impédance thermique dans le domaine fréquentiel a été formulée et a été utilisé pour extraire cette impédance en deçà de la fréquence de coupure thermique. Les paramètres thermiques ont été extraits par des simulations compactes grâce au modèle compact de transistors auquel un modèle électro-thermique a été ajouté via le nœud de température. Les travaux théoriques développés à ce jour pour la modélisation d'impédance thermique ont été vérifiés avec nos résultats expérimentaux. Il a été montré que, le réseau thermique classique utilisant un pôle unique n'est pas suffisant pour modéliser avec précision le comportement thermique transitoire et donc qu’un réseau plus complexe doit être utilisé. Ainsi, nous validons expérimentalement pour la première fois, le modèle distribué électrothermique de l'impédance thermique utilisant un réseau nodal récursif. Le réseau récursif a été vérifié par des simulations TCAD, ainsi que par des mesures et celles ci se sont révélées en excellent accord. Par conséquent, un modèle électro-thermique multi-géométries basé sur le réseau récursif a été développé. Le modèle a été vérifié par des simulations numériques ainsi que par des mesures de paramètre S à basse fréquence et finalement la conformité est excellente quelque soit la géométrie des dispositifsAn extensive evaluation of different techniques for transient and dynamic electro-thermal behavior of microwave SiGe:C BiCMOS hetero-junction bipolar transistors (HBT) and nano-scale metal-oxide-semiconductor field-effect transistors (MOSFETs) have been presented. In particular, new and simple approach to accurately characterize the transient self-heating effect, based on pulse measurements, is demonstrated. The methodology is verified by static measurements at different ambient temperatures, s-parameter measurements at low frequency region and transient thermal simulations. Three dimensional thermal TCAD simulations are performed on different geometries of the submicron SiGe:C BiCMOS HBTs with fT and fmax of 230 GHz and 290 GHz, respectively. A comprehensive evaluation of device self-heating in time and frequency domain has been investigated. A generalized expression for the frequency-domain thermal impedance has been formulated and that is used to extract device thermal impedance below thermal cut-off frequency. The thermal parameters are extracted through transistor compact model simulations connecting electro-thermal network at temperature node. Theoretical works for thermal impedance modeling using different networks, developed until date, have been verified with our experimental results. We report for the first time the experimental verification of the distributed electrothermal model for thermal impedance using a nodal and recursive network. It has been shown that, the conventional single pole thermal network is not sufficient to accurately model the transient thermal spreading behavior and therefore a recursive network needs to be used. Recursive network is verified with device simulations as well as measurements and found to be in excellent agreement. Therefore, finally a scalable electro-thermal model using this recursive network is developed. The scalability has been verified through numerical simulations as well as by low frequency measurements and excellent conformity has been found in for various device geometries
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Dalcanale, Stefano. « Reliability analysis of GaN HEMT for space applications and switching converters based on advanced experimental techniques and two dimensional device simulations ». Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3425311.
Texte intégralRésumé :
Gallium Nitride is a promising wide-bandgap material for electronics. With GaN based devices it is possible to achieve higher operative frequencies and power densities in comparison to Silicon. The first GaN-based High Electron Mobility Transistor (HEMT) has been designed in the 1995, and after twenty years this technology start to be ready to compete in the market with Silicon-based devices. There are several reason why it was necessary all this time to obtain a stable technology. Unlike Silicon, it is still not possible to grow a gallium nitride crystal starting from a seed, with reasonable quality dimensions and costs. Thus, itis necessary to grow it on different substrates, like Silicon Carbide, Sapphire
or Silicon. Therefore, the obtained crystals have a high defects concentration that limits the device performances. With the optimization of the process and the introduction suitable nucleation layer on the substrate it is now possible to grow GaN wafers with a tolerable defectivity. The main problems induced by the defects are trap states and reliability issues. The trap states generate problems during dynamic operation, inducing a drop in the output characteristics. In addition to this recoverable phenomena, the GaN-HEMTs can even present problem of reliability, that have been widely explored in the past. Nowadays, the estimated device life time of the last technologies allow to start the production of electronics both for consumer market than for the more demanding space applications.
Within this work it will be presented a summary of the research activity performed during my PhD. In the first part is presented a short summary of the state of the art of GaN-HEMT technology. In the last two years a lot of new results have been demonstrated in literature, showing the last technological improvements. Then, a short summary on the trapping phenomena and reliability issue is presented, that is fundamental to understand all the obtained results.
The research activities involved the two main GaN-based HEMTs applications: the RF devices and the power switching transistors. For the RF applications the transistor is used as an amplifier, in a frequency range from 1 GHz to 100 GHz.
The main applications are radar and telecommunications for mobile phone, radio and satellites. I collaborated in a project of the European Space Agency, with subject “Preliminary Validation of Space Compatible Foundry Processes”. They will be presented all the results of the reliability assessment carried out within this project. The purpose was to validate a GaN-HEMT technology for space applications, trying to estimate the device lifetime and the failure mechanisms. We will see that the two analysed technologies are very stable, and the estimated life time exceed the twenty years. Nevertheless, not all the failure mechanisms are clear, but we found some degradation signatures that can be related to the gate metallization.
On the side of power switching transistors I will report first the results obtained in a collaboration with ON Semiconductor on the development of d-mode MIS-HEMTs. Our role was to give a feedback on the device performance improvement, mainly focused on the on-resistance. It represents indeed one of the main problems of GaN-HEMT working in switching conditions and it is mainly related to trapping phenomena. Then, we developed a new original measurement procedure that allows to test the devices in a condition closer to the operative one. This new setup helps us to demonstrate the impressive stability of the last device generations. Now this technology is ready to work at 600 V in switching operation, with performances better than Silicon.
The second part about the power devices will report the work carried out during the period by the Ferdinand-Braun-Institut, Leibniz-Institut für Hochfrequenztechnik (FBH), in Berlin. The target was to investigate the reliability of the p-GaN devices developed by the research center by means of long term on-state life test. The gate leakage current is suspected to be one of the main problem for the reliability of this kind of device in on-state operation. However, there are not many works in literature that analyse this issue, and we will see how our test helps to consolidate one of the proposed degradation modes. Within this analysis it was fundamental the role of physical based simulations, for which is devoted a separated chapter. The simulations were very helpful for the understanding of the degradation mechanism. They allowed us to have a complete vision of the conduction mechanisms and of the device weakness. In this way we can give fundamental information to the device developers, in particular which device regions need to be improved.Il nitruro di gallio è un promettente materiale a semiconduttore con ampio energy gap. Tramite dispositivi bastai su GaN è possibile raggiungere frequenze operative e densità di potenza maggiori in confronto al silicio. Il primo transistor HEMT (High Electron Mobility Transistor) basato su GaN è stato sviluppato nel 1995, e dopo vent'anni questa tecnologia inizia ad essere pronta a competere sul mercato con dispositivi basati su silicio. Ci sono diversi motivi per cui è servito del tempo per ottenere una tecnologia stabile. A differenza del silicio, non è possibile crescere cristalli di nitruro di gallio partendo da un seme, non almeno con costi, qualità e dimensioni ragionevoli. Perciò è necessario crescere il nitruro di gallio su substrati diversi, come il carburo di silicio, lo zaffiro o il silicio. Perciò, i cristalli ottenuti hanno una concentrazione di difetti che limita le prestazioni dei dispositivi. Con l'ottimizzazione del processo e l'introduzione di un adeguato strato di transizione, detto nucleation layer, è possibile ottenere dei wafer con una difettività tollerabile. Il problema principale introdotto dai difetti sono gli stati trappola e questioni di affidabilità. Gli stati trappola danno problemi durante il funzionamento dei transistor, creando un calo temporaneo della caratteristica di uscita. Oltre a questo fenomeno temporaneo gli HEMT basati su GaN presentano problemi di affidabilità, ampiamente studiati in passato. Al giorno d'oggi il tempo di vita medio stimato delle ultime generazioni di transistor permette la produzione di dispositivi elettronici sia per il settore commerciale che per applicazioni spaziali. In questo lavoro sarà presentato un riassunto delle attività di ricerca svolte durante il dottorato. Nella prima parte è presentato un riepilogo dello stato dell'arte della tecnologia GaN-HEMT. Negli ultimi due anni in letteratura sono stati dimostrati nuovi risultati, rivelando un notevole miglioramento tecnologico. Verrà poi presentato un breve riassunto sui fenomeni di trapping e sull'affidabilità, che risulterà fondamentale per comprendere al meglio i risultati ottenuti. Le attività di ricerca hanno coinvolto le due applicazioni principali dei transistor GaN-HEMT: i dispositivi RF e i transistor di potenza. Per applicazioni RF il transistor è usato come amplificatore, in un range di frequenze tra 1 GHz e 100 GHz. Le applicazioni principali sono radar e telecomunicazioni per telefonia mobile, radio e satellitare. Ho collaborato in un progetto dell'Agenzia Spaziale Europea dal titolo: “Preliminary Validation of Space Compatible Foundry Processes”. Verranno presentati i risultati della valutazione dell'affidabilità svolta in questo progetto. Lo scopo era di validare la tecnologia GaN-HEMT per applicazioni spaziali, provando a stimare il tempo di vita dei dispositivi e i meccanismi di guasto. Vedremo come la tecnologia analizzata sia stabile, con un tempo di vita stimato che oltrepassa i vent'anni. Ciò nonostante, non sono ancora chiari tutti i meccanismi di guasto, ma è stata trovata qualche caratteristica tipica del degrado legata alla metallizzazione di gate. Dal lato dei transistor di potenza verranno riportati prima i risultati ottenuti nella collaborazione con ON Semiconductor, nello sviluppo di dispositivi MISHEMT normally-on. Il nostro ruolo era di dare un feedback all'azienda riguardo alle performance dei dispositivi, in particolare in termini di resistenza in on-state. Questo rappresenta infatti uno dei problemi maggiori dei transistor GaNHEMT che lavorano in condizioni switching ed è dovuto a fenomeni di trapping. Poi, è stato sviluppata una nuova procedura di misura che permette di testare i dispositivi in condizione vicine a quelle operative. Questo nuovo setup è stato d'aiuto per dimostrare l'eccezionale stabilità delle ultime generazioni di transistor. Ora questa tecnologia è pronta per lavorare a 600 V con prestazioni migliori di quelle del silicio. La seconda parte relativa ai dispositivi di potenza parlerà del lavoro svolto presso il Ferdinand-Braun-Institut, Leibniz-Institut für Hochfrequenztechnik (FBH), a Berlino. L'obiettivo principale era quello di investigare l'affidabilità dei dispositivi p-GaN sviluppati presso il centro di ricerca, tramite stress in on-state a lungo termine. La corrente di leakage di gate è sospettata di essere uno dei problemi principali per l'affidabilità di questo tipo di dispositivi in on-state. Tuttavia, non ci sono tanti lavori in letteratura che analizzano il problema, e si vedrà come i test svolti aiutano a consolidare uno dei modelli proposti. In questa analisi è stato fondamentale il ruolo delle simulazioni, a cui è stato riservato un capitolo a parte. Le simulazioni sono state di grande aiuto nella comprensione dei meccanismi di guasto e hanno permesso di avere una visione completa dei meccanismi di conduzione e dei punti deboli del dispositivo. In questo modo possono essere date informazioni essenziali a chi sviluppa i transistor, in particolare quali sono le regioni del dispositivo che andrebbero migliorate.
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Canada, Justin M. « A Comparison of Maximal Exercise Responses among Patients with a Total Artificial Heart, a Left Ventricular Assist Device, or Advanced Heart Failure ». VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/340.
Texte intégralRésumé :
The purpose of this study was to evaluate graded exercise responses to treadmill exercise in patients with a total artificial heat (SynCardia, Tucson, AZ). Additionally, this study sought to compare the exercise response in total artificial heart (TAH) patients to both advanced heart failure (HF) patients on medical management only and HeartMate II (Thoratec Corp., Pleasanton, CA) left‐ventricular assist device (HMII) patients. For patients with biventricular heart failure the TAH is a viable option to bridge patients until transplant becomes available. Its demonstrated improvement in mortality and increasing usage necessitates a shift in focus to quality of life in the TAH patient including functional ability. The evaluation of cardiorespiratory responses to graded exercise provides an objective measure of functional ability. There is very limited information in the literature on the exercise response of the mechanical circulatory support (MCS) device patient, particularly the TAH patient. A review was performed on MCS patients who underwent symptom‐limited cardiopulmonary exercise testing (CPET) following device implant of either TAH or HMII. ANOVA was performed to compare differences between the two device groups and HF patients listed for heart transplant. Fourteen TAH patients underwent CPET (9 male, 5 female) with peak oxygen consumption (VȩO2) of 0.926 + .168 L∙min, 36 + 8% % predicted, 11.0 + 2.3 ml.kg.min or 3.1 + 0.7 METs. Ventilatory anaerobic threshold (VAT) was 0.706 + .181 L∙min. Peak (VȩO2, % pred. (VȩO2 and VAT were significantly lower in the TAH compared with HMII and advanced HF (p = 0.0012, p = 0.0106, p = 0.0009, respectively). Peak RER was significantly higher (p = <.0001) and OUES was significantly lower (p = 0.0004) in the TAH. Exercise capacity is significantly reduced in the TAH patient below that observed in HMII LVAD and advanced HF patients. This provides a baseline for expected functional status and has implications on the ADL tolerance of these individuals. The next step is to develop strategies to ameliorate this continued exercise intolerance. The documents herein contain a review of literature including a background in heart failure and the use of the exercise response in the heart failure patient. An overview is also presented on the use of MCS describing physiology, device function, and exercise physiology of the MCS device patient. A manuscript has also been included detailing a cross‐sectional review of the effects of graded exercise in the TAH patient and comparing it to the HMII and advanced HF patient.
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Otto, Ernst. « Development of superconducting bolometer device technology for millimeter-wave cosmology instruments ». Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:30a1103a-ea7a-4b08-ba92-665cbd9740e0.
Texte intégralRésumé :
The Cold-Electron Bolometer (CEB) is a sensitive detector of millimeter-wave radiation, in which tunnel junctions are used as temperature sensors of a nanoscale normal metal strip absorber. The absorber is fed by an antenna via two Superconductor-Insulator-Normal metal (SIN) tunnel junctions, fabricated at both ends of the absorber. Incoming photons excite electrons, heating the whole electron system. The incoming RF power is determined by measuring the tunneling current through the SIN junctions. Since electrons at highest energy levels escape the absorber through the tunnel junctions, it causes cooling of the absorber. This electron cooling provides electro-thermal feedback that makes the saturation power of a CEB well above that of other types of millimeter-wave receivers. The key features of CEB detectors are high sensitivity, large dynamic range, fast response, easy integration in arrays on planar substrates, and simple readout. The high dynamic range allows the detector to operate under relatively high background levels. In this thesis, we present the development and successful operation of CEB, focusing on the fabrication technology and different implementations of the CEB for efficient detection of electromagnetic signals. We present the CEB detector integrated across a unilateral finline deposited on a planar substrate. We have measured the finline-integrated CEB performance at 280-315 mK using a calibrated black-body source mounted inside the cryostat. The results have demonstrated strong response to the incoming RF power and reasonable sensitivity. We also present CEB devices fabricated with advanced technologies and integrated in log-periodic, double-dipole and cross-slot antennas. The measured CEB performance satisfied the requirements of the balloon-borne experiment BOOMERANG and could be considered for future balloon-borne and ground-based instruments. In this thesis we also investigated a planar phase switch integrated in a back-to-back finline for modulating the polarization of weak electromagnetic signals. We examine the switching characteristics and demonstrate that the switching speed of the device is well above the speed required for phase modulation in astronomical instruments. We also investigated the combination of a detector and a superconducting phase switch for modulating the polarization of electromagnetic radiation.
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SANTOS, Marcos Graciano. « Mecanismos de Identificação de Proximidade e Alocação de Recursos para uma Comunicação D2D Energeticamente Eficiente em Redes LTE-A ». Universidade Federal de Pernambuco, 2014. https://repositorio.ufpe.br/handle/123456789/11573.
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Atualmente, mais de 200 milhões de usuários utilizam as redes 3G/LTE (Long Term Evolution). Com este aumento crescente de usuários com acesso sem fio, muitas pesquisas se concentram no esforço de desenvolvimento de soluções que permitam atender às demandas de redes com alta disponibilidade e altas taxas de transmissão sem considerar, em geral, as limitações de bateria dos dispositivos. Como requisito do LTE Advanced (especificações para a Quarta Geração de comunicações móveis) incluem-se os Serviços de Proximidade, comunicação denominada de dispositivo a dispositivo (D2D, do inglês: device-to-device) para atender ao desenvolvimento de novas demandas de serviços, como jogos e vídeos on-line ou transferência de conteúdos, aplicações que, a cada dia, requerem maiores consumos de energia. Neste trabalho, realizamos medições que avaliam o consumo da comunicação dispositivo-estação base e propomos primeiramente um algoritmo de identificação de pares de dispositivos e definição de limiares de referência, diferentemente de outros trabalhos, com base nas características de consumo dos dispositivos, que viabilize comunicação direta D2D energeticamente mais eficiente que a comunicação convencional via estação rádio base. Em seguida, para cenários de grande aglomeração de pessoas, uma alternativa de serviço de disponibilização de conteúdos ou transferência de arquivos através de um novo padrão de alocação de recursos, utilizando o modo duplex por divisão no tempo (TDD – Time Duplex Division). Foram considerados cinco modelos de propagação distintos para comparação do desempenho, tomando como base uma situação real num parque do Recife considerando a transmissão de um vídeo em alta definição. Por fim, tratamos a questão da segurança com uma criptografia específica entre os dispositivos próximos. Os resultados são avaliados via simulação utilizando-se o Matlab, demonstrando a eficácia da solução com reduções de até 43% no consumo de energia da bateria do dispositivo.
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Cintura, Manuel. « An Embedded Data Logger for In-Vehicle Testing ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23841/.
Texte intégralRésumé :
This thesis describes an embedded data logger project, composed of software part (in C++ language) and hardware part (Raspberry Pi). It is illustrated the whole procedure from the start of the project with requirements to the end with the experimental results and validation phase. The device is able to acquire, in a synchronous way, videos, CAN and Serial logs from the vehicle under test.
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POLI, ANNAMARIA. « Analisi, progetto e sviluppo di ausilio per il superamento delle barriere visivo-percettive cromatiche ». Doctoral thesis, Politecnico di Milano, 2007. http://hdl.handle.net/10281/140159.
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VAHLBERG, ANNA. « Textile Sensor Using Piezoelectric Fibers for Measuring Dynamic Compression in a Bowel Stent ». Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17999.
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In this experimental study the in-lined poled piezoelectric poly(vinylidene fluoride)(PVDF) bicomponent fiber was investigated the suitability in applications within the area of textile sensors when used in a bowel stent. Today there are only piezoelectric films made of PVDF available. Compared to a film, a fiber increases the amounts of application abilities. In this study a plain weave, resembling a coordinate system was made of the piezoelectric PVDF fiber and tested on top of two different beds; one hard and one elastic made of foam. The structure was then developed into two structures; one integrated in the stents structure with a plain weave pattern and one secondary structure as a plain weave placed onto the stent. Two test methods were developed in order to resemble the bowel movements to test the two piezoelectric PVDF fiber based structures. A reliability test in a reometer was made of the fiber, giving high differences in mean values. An in vivo test was conducted in a pig where the stent was placed in the orifice of the stomach. Both structures shown response when both developed methods was used. Due to large irregularities within the piezoelectric PVDF fiber the evaluation between the two structures was not possible. The most favorable structure was the secondary structure due to the larger continuous process ability and application areas. It was also seen that the reliability of the piezoelectric PVDF fiber is low, giving a non-reliable sensor.Program: Textilteknik
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Merwaday, Arvind. « Stochastic Geometry Based Analysis of Capacity, Mobility and Energy Efficiency for Dense Heterogeneous Networks ». FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2480.
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In recent years, the increase in the population of mobile users and the advances in computational capabilities of mobile devices have led to an exponentially increasing traffic load on the wireless networks. This trend is foreseen to continue in the future due to the emerging applications such as cellular Internet of things (IoT) and machine type communications (MTC). Since the spectrum resources are limited, the only promising way to keep pace with the future demand is through aggressive spatial reuse of the available spectrum which can be realized in the networks through dense deployment of small cells. There are many challenges associated with such densely deployed heterogeneous networks (HetNets). The main challenges which are considered in this research work are capacity enhancement, velocity estimation of mobile users, and energy efficiency enhancement.
We consider different approaches for capacity enhancement of the network. In the first approach, using stochastic geometry we theoretically analyze time domain inter-cell interference coordination techniques in a two-tier HetNet and optimize the parameters to maximize the capacity of the network. In the second approach, we consider optimization of the locations of aerial bases stations carried by the unmanned aerial vehicles (UAVs) to enhance the capacity of the network for public safety and emergency communications, in case of damaged network infrastructure. In the third approach, we introduce a subsidization scheme for the service providers through which the network capacity can be improved by using regulatory power of the government. Finally, we consider the approach of device-to-device communications and multi-hop transmissions for enhancing the capacity of a network.
Velocity estimation of high speed mobile users is important for effective mobility management in densely deployed small cell networks. In this research, we introduce two novel methods for the velocity estimation of mobile users: handover-count based velocity estimation, and sojourn time based velocity estimation. Using the tools from stochastic geometry and estimation theory, we theoretically analyze the accuracy of the two velocity estimation methods through Cramer-Rao lower bounds (CRLBs).
With the dense deployment of small cells, energy efficiency becomes crucial for the sustained operation of wireless networks. In this research, we jointly study the energy efficiency and the spectral efficiency in a two-tier HetNet. We optimize the parameters of inter-cell interference coordination technique and study the trade-offs between the energy efficiency and spectral efficiency of the HetNet.
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Schuette, Michael L. « Advanced processing for scaled depletion and enhancement-mode AlGaN/GaN HEMTs ». The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275524410.
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Kim, Alexander. « Switching-Loss Measurement of Current and Advanced Switching Devices for Medium-Power Systems ». Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/34568.
Texte intégralRésumé :
The ultimate goal for power electronics is to convert one form of raw electrical energy into a usable power source with the lowest amount of loss. A considerable portion of these losses are due to the use of switching devices themselves. Device losses can be apportioned to conduction loss and switching loss. It is commonly known and practiced that conduction loss can be reduced by driving MOSFETs and IGBTs harder with gate voltages closer to the maximum rating. This lowers the voltage across the device in the path of the amplified current and ultimately reduces power dissipated by the device. However, switching losses of these devices are not as easily characterized or intuitive for power electronics designers. This is mainly due to the fact that the parasitic reactive elements are nonlinear and not as readily documented as I-V characteristics of a given power device. For example, non-linear parasitic capacitances in the device are given for a fixed frequency across a voltage sweep. Parasitic inductance is typically not even mentioned in the datasheet. The switching losses of these devices depend on these mysterious reactances. A functional way to obtain estimates
of switching loss is to test the device under the conditions the device will be used. However, this task must be approached carefully in order to accurately measure the voltage and current of the device. Measurement devices also have parasitic impedances of their own that can add or subtract to switching energy during turn on or turn off and create misleading results. Preliminary testing was performed on multiple devices. After preliminary testing and deliberation, a device-measurement printed circuit board was made to easily replace switching devices of the same package.
This thesis presents switching loss measurements of medium-power capable devices in the tens of kW range. It also aims to attribute characteristics of switching voltage and current waveforms to the internal structure of the devices. The device tester designed is versatile since the output buffer of the gate drive is comprised of D-PAK totem pole BJTs. This is able to drive both current and voltage driven devices, i.e. SiC J-FETs (current-driven) and other voltage-driven devices (i.e. MOSFETs and IGBTs). It also allows for TO-220 and TO-247 packaged power diodes.Master of Science
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Arenas, Joshua A. « Evaluation of a Novel Myoelectric Training Device ». VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4050.
Texte intégralRésumé :
Recent technological developments have implemented the use of proportional control in prosthetic hands, giving rise to the importance of appropriate myoelectric control. EMG models in the past have assumed a linear proportionality to simplify the EMG-force relationships. However, it has been shown that a non-linear EMG-force relationship may be a more effective model. This study focused on evaluating three different control algorithms for a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the distal muscles in the arm. Sixteen healthy adult subjects (5 male and 11 female) with an average age of 23.6 years (SD = 2.7) were asked to drive the car through a slalom course. Completion times as well as number of errors (wall hits, cone hits, and reversals) were recorded to evaluate performance. The NASA TLX was administered to evaluate psychometrics such as mental demand, physical demand, frustration, and overall workload. The average total errors per trial on the final day of testing using the linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and non-linear proportional. The average course completion time per trial and overall workload using the non-linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and linear proportional. These results suggest that a non-linear algorithm would be most appropriate for myoelectric control in prosthetic hands.
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Asuni, Ganiyu. « Investigation of Advanced Dose Verification Techniques for External Beam Radiation Treatment ». Medical Physics, 2012. http://hdl.handle.net/1993/21706.
Texte intégralRésumé :
Intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) have been introduced in radiation therapy to achieve highly conformal dose distributions around the tumour while minimizing dose to surrounding normal tissues. These techniques have increased the need for comprehensive quality assurance tests, to verify that customized patient treatment plans are accurately delivered during treatment. In vivo dose verification, performed during treatment delivery, confirms that the actual dose delivered is the same as the prescribed dose, helping to reduce treatment delivery errors. In vivo measurements may be accomplished using entrance or exit detectors. The objective of this project is to investigate a novel entrance detector designed for in vivo dose verification.
This thesis is separated into three main investigations, focusing on a prototype entrance transmission detector (TRD) developed by IBA Dosimetry, Germany. First contaminant electrons generated by the TRD in a 6 MV photon beam were investigated using Monte Carlo (MC) simulation. This study demonstrates that modification of the contaminant electron model in the treatment planning system is required for accurate patient dose calculation in buildup regions when using the device. Second, the ability of the TRD to accurately measure dose from IMRT and VMAT was investigated by characterising the spatial resolution of the device. This was accomplished by measuring the point spread function with further validation provided by MC simulation. Comparisons of measured and calculated doses show that the spatial resolution of the TRD allows for measurement of clinical IMRT fields within acceptable tolerance. Finally, a new general research tool was developed to perform MC simulations for VMAT and IMRT treatments, simultaneously tracking dose deposition in both the patient CT geometry and an arbitrary planar detector system, generalized to handle either entrance or exit orientations. It was demonstrated that the tool accurately simulates dose to the patient CT and planar detector geometries. The tool has been made freely available to the medical physics research community to help advance the development of in vivo planar detectors.
In conclusion, this thesis presents several investigations that improve the understanding of a novel entrance detector designed for patient in vivo dosimetry.
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Hartwig, Jason W. « Liquid Acquisition Devices for Advanced In-Space Cryogenic Propulsion Systems ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1396562473.
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Allam, Sabry. « Acoustic modelling and testing of advanced exhaust system components for automotive engines ». Doctoral thesis, KTH, Aeronautical and Vehicle Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49.
Texte intégralRésumé :
The increased use of the diesel engine in the passenger car, truck and bus market is due to high efficiency and lower fuel costs. This growing market share has brought with it several environmental issues for instance soot particle emission. Different technologies to remove the soot have been developed and are normally based on some kind of soot trap. In particular for automobiles the use of diesel particulate traps or filters (DPF:s) based on ceramic monolithic honeycombs are becoming a standard. This new exhaust system component will affect the acoustics and also work as a muffler. To properly design exhaust systems acoustic models for diesel particulate traps are needed. The first part of this thesis considers the modelling of sound transmission and attenuation for traps that consist of narrow channels separated by porous walls. This work has resulted in two new models an approximate 1-D model and a more complete model based on the governing equations for a visco-thermal fluid. Both models are expressed as acoustic 2-ports which makes them suitable for implementation in acoustic software for exhaust systems analysis. The models have been validated by experiments on clean filters at room temperature with flow and the agreement is good. In addition the developed filter models have been used to set up a model for a complete After Treatment Device (ATD) for a passenger car. The unit consisted of a chamber which contained both a diesel trap and a Catalytic Converter (CC). This complete model was also validated by experiments at room temperature. The second part of the thesis focuses on experimental techniques for plane wave decomposition in ducts with flow. Measurements in ducts with flow are difficult since flow noise (turbulence) can strongly influence the data. The difficulties are also evident from the lack of good published in-duct measurement data, e.g., muffler transmission loss data, for Mach-numbers above 0.1-0.2. The first paper in this part of the thesis investigates the effect of different microphone mountings and signal processing techniques for suppressing flow noise. The second paper investigates in particular flow noise suppression techniques in connection with the measurement of acoustic 2-ports. Finally, the third paper suggests a general wave decomposition procedure using microphone arrays and over-determination. This procedure can be used to determine the full plane wave data, e.g., the wave amplitudes and complex wave numbers k+ and k-. The new procedure has been applied to accurately measure the sound radiation from an unflanged pipe with flow. This problem is of interest for correctly determining the radiated power from an engine exhaust outlet. The measured data for the reflection coefficient and end correction have been compared with the theory of Munt [33] and the agreement is excellent. The measurements also produced data for the damping value (imaginary part of the wavenumber) which were compared to a model suggested by Howe [13]. The agreement is good for a normalized boundary layer thickness less than 30-40
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Hirashima, Hideaki. « Establishment of machine and patient-specific quality assurance methods for advanced volumetric modulated arc therapy ». Kyoto University, 2019. http://hdl.handle.net/2433/242352.
Texte intégral
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Amir, Faisal. « Advanced physical modelling of step graded Gunn Diode for high power TeraHertz sources ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/advanced-physical-modelling-of-step-graded-gunn-diode-for-high-power-terahertz-sources(d0fea62f-ed98-4fa7-8a97-cb89776c08cd).html.
Texte intégralRésumé :
The mm-wave frequency range is being increasingly researched to close the gap between 100 to 1000 GHz, the least explored region of the electromagnetic spectrum, often termed as the 'THz Gap'. The ever increasing demand for compact, portable and reliable THz (Terahertz) devices and the huge market potential for THz system have led to an enormous amount of research and development in the area for a number of years. The Gunn Diode is expected to play a significant role in the development of low cost solid state oscillators which will form an essential part of these THz systems.Gunn and mixer diodes will 'power' future THz systems. The THz frequencies generation methodology is based on a two-stage module. The initial frequency source is provided by a high frequency Gunn diode and is the main focus of this work. The output from this diode is then coupled into a multiplier module. The multiplier provides higher frequencies by the generation of harmonics of the input signal by means of a non-linear element, such as Schottky diode Varactor. A realistic Schottky diode model developed in SILVACOTM is presented in this work.This thesis describes the work done to develop predictive models for Gunn Diode devices using SILVACOTM. These physically-based simulations provide the opportunity to increase understanding of the effects of changes to the device's physical structure, theoretical concepts and its general operation. Thorough understanding of device physics was achieved to develop a reliable Gunn diode model. The model development included device physical structure building, material properties specification, physical models definition and using appropriate biasing conditions.The initial goal of the work was to develop a 2D model for a Gunn diode commercially manufactured by e2v Technologies Plc. for use in second harmonic mode 77GHz Intelligent Adaptive Cruise Control (ACC) systems for automobiles. This particular device was chosen as its operation is well understood and a wealth of data is available for validation of the developed physical model. The comparisons of modelled device results with measured results of a manufactured device are discussed in detail. Both the modelled and measured devices yielded similar I-V characteristics and so validated the choice of the physical models selected for the simulations. During the course of this research 2D, 3D rectangular, 3D cylindrical and cylindrical modelled device structures were developed and compared to measured results.The injector doping spike concentration was varied to study its influence on the electric field in the transit region, and was compared with published and measured data.Simulated DC characteristics were also compared with measured results for higher frequency devices. The devices mostly correspond to material previously grown for experimental studies in the development of D-band GaAs Gunn devices. Ambient temperature variations were also included in both simulated and measured data.Transient solutions were used to obtain a time dependent response such as determining the device oscillating frequency under biased condition. These solutions provided modelled device time-domain responses. The time-domain simulations of higher frequency devices which were developed used modelling measured approach are discussed. The studied devices include 77GHz (2nd harmonic), 125 GHz (2nd harmonic) and 100 GHz fundamental devices.During the course of this research, twelve research papers were disseminated. The results obtained have proved that the modelling techniques used, have provided predictive models for novel Transferred Electron Devices (TEDs) operating above 100GHz.
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Lauer, Peter. « Advanced Proportional Servo Valve Control with Customized Control Code using White Space ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199441.
Texte intégralRésumé :
An industrial control valve has been designed by Eaton (AxisPro® valve). The servo performance valve has onboard electronics that features external and internal sensor interfaces, advanced control modes and network capability. Advanced control modes are implement in the valves firmware. With the help of the white space it is possilbe to execute custom code directly on the valve that interact with these controls. Small OEM applications, like rubber moulding machines, benefit from the comination of build in controls and custom code, to provide adaptations for their special machines.
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Proctor, Martin J. « Ultrasound power measurement : a microprocessor based device utilising thermal expansion of a total absorber ». Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU009820.
Texte intégralRésumé :
A new type of ultrasound power meter is described which is robust, portable, easy to operate and therefore suitable for use in the work place by non-specialist personnel. The device should be of particular value in the field of ultrasonic therapy, where a lack of suitable instrumentation has discouraged performance monitoring of ultrasound machines in the past although numerous surveys have found the calibration of such equipment generally to be poor. The mode of operation is based on absorption of the ultrasound beam within a liquid, which expands as the energy becomes degraded to heat. The rate of this thermal expansion is monitored by means of a capacitative liquid level sensor, the output signal being suitably processsed and passed to a microcomputer for analysis. Correction for interchange of heat with the surroundings is carried out automatically by the micro, by recording the 'background drift' in liquid volume for a few seconds prior to insonation and subtracting this from the expansion rate observed during input of ultrasound. Calibration is achieved by measuring the (corrected) expansion rates brought about by known powers supplied from an electrical heating coil. When using the new power meter for measurements of therapeutic ultrasound the performance compares favourably with that of other techniques: the reproducibility is on the order of 5% above about 0.5W, becoming less good below this (reaching about 20% at the minimum measurable power of 25-50mW). Design modifications which may improve performance at low power levels and possibly allow measurement of dignostic ultrasound are suggested.
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Jang, Yong-Kyu. « ADVANCED UNDERSTANDING OF THE OPTICAL PROPERTIES IN PHASE COMPENSATED LIQUID CRYSTAL DEVICES ». Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1185484614.
Texte intégral
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Grézaud, Romain. « Commande de composants grand gap dans un convertisseur de puisance synchrone sans diodes ». Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT107/document.
Texte intégralRésumé :
Les composants de puissance grand gap présentent d'ores et déjà des caractéristiques statiques et dynamiques supérieures à leurs homologues en silicium. Mais ces composants d'un nouvel ordre s'accompagnent de différences susceptibles de modifier le fonctionnement de la cellule de commutation. Les travaux qui furent menés au cours de cette thèse se sont intéressés aux composants grand gap et à leur commande au sein d'un convertisseur de puissance synchrone robuste, haut rendement et haute densité de puissance. En particulier deux points critiques ont été identifiés et étudiés. Le premier est la grande sensibilité des composants grand gap aux composants parasites. Le second est l'absence de diode parasite interne entre le drain et la source de nombreux transistors grand gap. Pour répondre aux exigences de ces nouveaux composants et en tirer le meilleur profit, nous proposons des solutions innovantes, robustes, efficaces et directement intégrables aux circuits de commande. Des circuits de commande entièrement intégrés ont ainsi été conçus spécifiquement pour les composants grand gap. Ceux-ci permettent entre autres le contrôle précis des formes de commutation par l'adaptation de l'impédance de grille, et l'amélioration de l'efficacité énergétique et de la robustesse d'un convertisseur de puissance à base de composants grand sans diodes par une gestion dynamique et locale de temps morts très courtsWide band gap devices already demonstrate static and dynamic performances better than silicon transistors. Compared to conventional silicon devices these new wide band gap transistors have some different characteristics that may affect power converter operations. The work presented in this PhD manuscript deals with a specific gate drive circuit for a robust, high power density and high efficiency wide band gap devices-based power converter. Two critical points have been especially studied. The first point is the higher sensitivity of wide band gap transistors to parasitic components. The second point is the lack of parasitic body diode between drain and source of HEMT GaN and JFET SiC. In order to drive these new power devices in the best way we propose innovative, robust and efficient solutions. Fully integrated gate drive circuits have been specifically developed for wide band gap devices. An adaptive output impedance gate driver provides an accurate control of wide band gap device switching waveforms directly on its gate side. Another gate drive circuit improves efficiency and reliability of diode-less wide band gap devices-based power converters thanks to an auto-adaptive and local dead-time management
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Lafaye, Christophe. « Le génie en Afghanistan : adaptation d'une arme en situation de contre-insurrection (2001-2012) : hommes, matériels, emploi ». Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM1041.
Texte intégralRésumé :
Cette recherche doctorale en histoire immédiate, s'inscrit dans une réflexion plus large sur l'étude de nouveaux conflits, la culture et l'emploi des forces armées françaises sur le terrain, en prenant l'exemple de son engagement en Afghanistan. Elle porte particulièrement sur l'emploi de l'arme du génie dont nous postulons à la grande importance de ses savoir-faire sur le terrain, en situation de contre-insurrectionThis doctoral research takes part on the study of the new conflicts, by taking the example of the French engineers in Afghanistan. We postulate for the big importance of these combat support units in situation of counterinsurgency
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Pugliano, Marion. « Conception et optimisation d'un implant thérapeutique combiné à des organoïdes de cellules souches pour la nanomédecine régénérative ostéoarticulaire ». Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ111.
Texte intégralRésumé :
Notre équipe a mis au point une stratégie innovante d’implants thérapeutiques biphasiques, pour une régénération plus efficace et plus durable du cartilage articulaire, dans le cadre du traitement des lésions ostéochondrales. Ces implants pourraient représenter de meilleures alternatives aux traitements actuellement utilisés en chirurgie orthopédique. Dans un premier temps, nous avons élaboré un modèle d’implant thérapeutique à base de collagène de type II dérivé de méduse, fonctionnalisé par des nanoréservoirs de facteurs de croissance TGF-β3 et équipé de cellules souches mésenchymateuses humaines (hCSMs) dérivées de la moelle osseuse. La biocompatibilité et les propriétés chondrogéniques de cet implant ont été validées par des analyses in vitro, confirmant son potentiel thérapeutique pour la régénération du cartilage articulaire. Dans un second temps, nous nous sommes plus particulièrement concentrés sur la régénération de l’unité ostéochondrale. Il est en effet essentiel de régénérer un os sous-chondral sain, pour permettre une régénération stable du cartilage articulaire en surface. Dans ce but, nous avons développé un implant thérapeutique doté de deux compartiments : (i) un premier compartiment élaboré à partir d’un biomatériau synthétique de poly-ε-caprolactone (PCL), doté de nanoréservoirs de facteur de croissance BMP-7, pour la régénération de l’os sous-chondral : (ii) un second compartiment à base d’un hydrogel d’alginate et d’acide hyaluronique, ensemencé d’organoïdes hybrides de hCSMs et de chondrocytes humains, pour la régénération du cartilage articulaire. L’efficacité de cet implant biphasique a été confirmée in vitro et in vivo chez la souris. Dans un troisième temps, nous avons évalué notre stratégie d’implant thérapeutique biphasique en site intra-articulaire, chez l’animal de grande taille (brebis). Ces travaux ont permis de valider la faisabilité et l’efficacité de notre stratégie, combinant cette fois-ci : (i) un implant collagénique commercial, doté de nanoréservoirs de facteur de croissance BMP-2, pour la régénération de l’os sous-chondral ; (ii) un hydrogel d’alginate et d’acide hyaluronique, incorporant des organoïdes de CSMs de moelle osseuse de brebis, pour la régénération du cartilage articulaire. En conclusion, ces médicaments combinés de thérapie innovante, associant des biomatériaux naturels ou synthétiques (dispositif médical implantable), des molécules thérapeutiques et des cellules souches mésenchymateuses (médicament de thérapie innovante), permettent la régénération de l’unité ostéochondrale dans son ensemble. Cette stratégie novatrice permettra sans nul doute de grandes avancées en nanomédecine régénérative ostéoarticulaire, dans l’optique d’améliorer toujours plus le traitement et le confort des patientsOur team has developed an innovative strategy based on biphasic therapeutic implants allowing a more effective and long-lasting regeneration of articular cartilage in the treatment of osteochondral lesions. These implants may represent better alternatives to the current treatments used in orthopaedic surgery. First, we developed a jellyfish type II collagen therapeutic implant model, functionalized with TGF-β3 growth factor nanoreservoirs, and equipped with human bone marrow-derived mesenchymal stem cells (hMSCs). The biocompatibility and chondrogenic properties of this implant have been validated in vitro, confirming its therapeutic potential for the regeneration of articular cartilage. In a second time, we focused more on the regeneration of the osteochondral unit. Indeed, it is crucial to regenerate a healthy subchondral bone, to allow a stable regeneration of articular cartilage on the surface. To this end, we have developed a therapeutic implant with two compartments : (i) a first compartment based on a synthetic poly-ε-caprolactone (PCL) biomaterial, equipped with BMP-7 growth factor nanoreservoirs, for the regeneration of the subchondral bone ; (ii) a second compartment based on a hydrogel of alginate and hyaluronic acid, seeded with hybrid organoids of hMSCs and human chondrocytes, for the regeneration of the articular cartilage. The effectiveness of this biphasic implant has been confirmed in vitro and in vivo in mice. Thirdly, we evaluated our biphasic therapeutic implant strategy in the large animal (sheep). This work validated the feasibility and effectiveness of our strategy, by combining : (i) a commercial collagen implant with BMP-2 growth factor nanoreservoirs, for the regeneration of the subchondral bone ; (ii) a hydrogel of alginate and hyaluronic acid, incorporating organoids of sheep bone marrow MSCs, for the regeneration of articular cartilage. In conclusion, these combined advanced medicinal products (ATMPs), combining natural or synthetic biomaterials (implantable medical device), therapeutic molecules and mesenchymal stem cells, allow the regeneration of the entire osteochondral unit. This innovative strategy will undoubtedly lead to major advances in osteoarticular regenerative nanomedicine, aiming to improve the treatment and comfort of patients
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Chang, Meng-Jen, et 張夢仁. « Automatic Measurement for Device/Process Parameters Extraction of Advanced CMOS Device ». Thesis, 2001. http://ndltd.ncl.edu.tw/handle/00152933355850759911.
Texte intégralRésumé :
碩士國立臺北科技大學
機電整合研究所
89
The MOSFET is the building block of ULSI circuits in microprocessor and dynamics memories. In order to increase the packing density and to improve circuit performance, many researchers have invested their efforts in scaling down the CMOS device size. However, simply reducing device dimension without paying attention to other processing parameters will cause a variety of non-ideal characteristic. In CMOS technology, channel length is a key parameter used for device design and circuit simulation. Though many methods have been proposed for the extraction of effective channel length. Most of them are based on I-V measurement and some others are based on C-V measurement. But they are all failed as the generation goes down to quarter micron or beyond. In this thesis we proposed a new approach for extracting advanced CMOS device parameters by using a modified C-V method, named capacitance-ratio method (C-R method). According to the C-R method, we could determine the effective channel length , metallurgical channel length , process bias , extension overlap bias , source-to-drain series resistance , and the gate to drain capacitance easily. By the algorithm of C-R method, we want to develop an automatic measurement system to help extracting these parameters. With the help of automatic measurement system, one can easily extract parameters and monitor fabrication process. The greatest worth of the system is able to get reasonable and consistent results, besides the cost and time in measurement will be lower in future application. Finally, We show the ease of using our system to extract thin gate oxide parameter.
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Chen, Bo-Wei, et 陳柏暐. « Development of Advanced for Vacuum Suction Device ». Thesis, 2019. http://ndltd.ncl.edu.tw/handle/52fwn3.
Texte intégralRésumé :
碩士淡江大學
電機工程學系機器人工程碩士班
107
The main content of this paper is to Design and Implementation of Suction Fuzzy Controller for Vacuum Suction Device. The suction fuzzy controller is applied to the robot arm of mobile robot. In the storage and logistics system, a wide range of items, the arm in the process of picking up the goods, each product packaging material, weight, size, items will be related to the end of the mechanical arm of the vacuum adsorption device configuration and controller applications. Therefore, the design and implementation of the suction fuzzy controller for vacuum adsorption device are discussed and studied. Vacuum suction cups for the vacuum adsorption device of the key components, vacuum sucker material characteristics and shape are related to the robot arm in the picking goods can be successfully obtained, and in the handling process is stable, so this paper in addition to the vacuum adsorption device suction Fuzzy controller design and implementation, but also to strengthen the vacuum sucker to explore the experimental way to return to a variety of sucker suction characteristics.
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Su, Ming-Chi, et 蘇明啟. « Advanced Structure Design for SPR Bio-sensor Device ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/23307704499866161903.
Texte intégralRésumé :
碩士國立臺灣大學
醫學工程學研究所
93
Surface Plasmon Resonance (SPR) is a novel optical sensing technique with advantages of label-free, high sensitivity, real-time monitoring, versatility (bio-chemistry reaction, concentration of molecule), and parallel detection. This research is focused on the improvement of system component , and we using the structure designs of 1D multilayer and 2D grating for enhanced performance. Based on the theory of optical admittance loci diagram, we designed a new asymmetric multilayer structure to replace traditional single gold layer. We applied the periodic refractive index change of two dielectric materials (TiO2/SiO2) combined with bimetallic design (gold/silver). SPR angle can be modulated to 61.52°, and reduced HMBW to 0.25°. The signal is located in the suitable range of measurement system, and our new device has not only a larger dynamic measurable range (1.33~1.48), but also higher resolution (8.13x10-6). In our experiment, we measured the angular shift of SPR and the reflective intensity change at a fixed angle. The resolution of the device is 8.13x10-6RIU. The multilayer structure was also used to simulate the position of nano-particle in micro-fluid channel. In order to minimize our detection system, we used the grating structure composed of 2D honeycomb array to couple surface plasmon wave and found at at proper incident wavelength of 833nm and angle of 50° has good SPR signal.
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Wang, Yun. « High frequency techniques for advanced MOS device characterization ». 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17235.
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Lu, Wen-Chen, et 呂文琛. « An Advanced Study of Device-Free Indoor Localization ». Thesis, 2017. http://ndltd.ncl.edu.tw/handle/67523094982797137903.
Texte intégralRésumé :
碩士元智大學
電機工程學系
105
In a mordern society, the popularity of positioning brings us the convenience of life. In most of the indoor positioning system, the subjects often have to use the mobile phone, carrying a laptop or wearing a specic device to locate position. We proposed a Device-Free Indoor Localization, Subjects can locating themself without using or wearing any device. Recently, channel state information (CSI) has been adopted as an enhanced wireless channel measurement instead of received signal strength (RSS) for indoor WiFi positioning systems. Combine the concept of devicefree with Channel State Information (CSI), we can successfully solve the situation of the incapacity of getting the channel State Informaton from mobile phone. That is, the indoor positioning of the application level can be pushed more widely. It can also be used in smart home, automatic monitoring of the elderly and home security and so on. In this paper, a device-free indoor positioning system is proposed. Utilizing the concept of Deep Learning combined with channel state information to improve ngerprinting-based indoor positioning. The idea is to take out the megnitude and phase information from channel state information and reconstructing channel state information. Utilizing the algorithm of Deep Neural Network (DNN) , Recurrent Neural Network (RNN) to achieve indoor positioning. The results show that the eect of Recurrent Neural Network approach in indoor positioning works eectly.
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Deceglie, Michael Gardner. « Advanced Silicon Solar Cell Device Physics and Design ». Thesis, 2013. https://thesis.library.caltech.edu/7480/10/Deceglie%20CIT%20thesis.pdf.
Texte intégralRésumé :
A fundamental challenge in the development and deployment of solar photovoltaic technology is a reduction in cost enabling direct competition with fossil-fuel-based energy sources. A key driver in this cost reduction is optimized device efficiency, because increased energy output leverages all photovoltaic system costs, from raw materials and module manufacturing to installation and maintenance. To continue progress toward higher conversion efficiencies, solar cells are being fabricated with increasingly complex designs, including engineered nanostructures, heterojunctions, and novel contacting and passivation schemes. Such advanced designs require a comprehensive and unified understanding of the optical and electrical device physics at the microscopic scale. This thesis focuses on a microscopic understanding of solar cell optoelectronic performance and its impact on cell optimization. We consider this in three solar cell platforms: thin-film crystalline silicon, amorphous/crystalline silicon heterojunctions, and thin-film cells with nanophotonic light trapping. The work described in this thesis represents a powerful design paradigm, based on a detailed physical understanding of the mechanisms governing solar cell performance. Furthermore, we demonstrate the importance of understanding not just the individual mechanisms, but also their interactions. Such an approach to device optimization is critical for the efficiency and competitiveness of future generations of solar cells.
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MING-RU, YEN, et 顏民儒. « Relief Device Applications of Advanced High-tech Plant of Influencing FactorsRelief Device Applications of Advanced High-tech Plant of Influencing Factors ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/31300651964686326925.
Texte intégralRésumé :
碩士中州科技大學
工程技術研究所
101
With the development of technology, human’s reliability on a growing technology convenience has increase. Technology not only bring in convenience buy also brings enormous benefits worth. As the development of high-tech industry companies, the incoming disasters are more serious and dangerous compare to traditional industry plant. This research is focusing on the safety device in these high-tech plants. The multi directions research will suggest the safety device for these high tech plants. In this study, are surveys base on people who related to these high-tech facility. After analysis the result, suggesting high-tech plants by focusing on the safety device operator training when they purchase these safety device. Increase the safety device usage efficiency, and economical cost. In the future research, the researchers are able to increase the research area throughout the country with similar high-tech plants. This research can be the basic data for the future research, and able to focus on research analysis on other influence effect, or difference between each background effect.
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Chen, Yan-Hao, et 陳彥豪. « The Fabrication and Device Performances of Advanced Graphene Transistors ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/78659481941851438623.
Texte intégralRésumé :
碩士國立交通大學
光電工程研究所
102
Since the graphene ,two-dimensional material, was discovered in 2004, graphene transistors rapidly become a hot topic. Because of its high mobility and good conductivity, graphene can match the goals of high-speed operation, which is importance for the development of high-speed, high-performance transistors. In this thesis, we grow graphene on copper foil by using a low-pressure chemical vapor deposition system. By using difference sample structures, we will investigate the characteristic of graphene transistors. Generally, this thesis can be divided into three parts. Firstly, we will introduce the preparation of graphene films and graphene transistors. Next, we design dual-gated (in-plane and bottom gates) graphene filed-effect transistors and investigate it. We find that it is effective to tune Fermi level in graphene channels by changing the voltages of in-plane gates. Finally, we design one-cut and dual-cut graphene filed effect transistors scraped by using atomic force microscope tips. In these devices, the current is forced to squeeze into the path between the two cuts rather than flow directly through the graphene sheet. We have observed that the gate voltages under minimum current conditions shift toward zero bias as the sizes of the dual-cut regions increase. These results have demonstrated an interesting architecture for device fabrication, Fermi level tuning, and device applications.