Dissertations / Theses on the topic 'Electrical and Electronic Engineering'
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Navaraj, William Ringal Taube. "Inorganic micro/nanostructures-based high-performance flexible electronics for electronic skin application." Thesis, University of Glasgow, 2019. http://theses.gla.ac.uk/40973/.
Full textGalda, Alexey. "Electronic properties of Luttinger Liquid with electron-phonon interaction." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4293/.
Full textLarsson, Erik, and Niklas Kron. "Independent project in electrical engineering : Magnetic hand timepiece." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325637.
Full textPaine, Stephen Thomas. "Electronic countermeasures applied to passive radar." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/30945.
Full textSiebert, Wolfgang Peter. "Alternative electronic packaging concepts for high frequency electronics." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223.
Full textLund, Richard. "Multilevel Power Electronic Converters for Electrical motor Drives." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-687.
Full textPower electronic converters are widely used in industrial power conversion systems both for utility and drives applications. As the power level increases, the voltage level is increased accordingly to obtain satisfactory efficiency. During the last years, the voltage rating of fast switching high voltage semiconductors such as the Insulated Gate Bipolar Transistor (IGBT) has increased. Still, there is a need for series connection of switching devices. In this area of applications, the Multilevel Converter has shown growing popularity.
The fundamental advantages of the Multilevel Converter topologies are low distorted output waveforms and limited voltage stress on the switching devices. The main disadvantages are higher complexity and more difficult control.
In this thesis, Multilevel Converters are analysed for large motor drive applications. The main focus has been on converter losses, output waveform quality and control.
Analytical expressions for both switching and conduction losses for 4- and 5-level Diode Clamped Converters have been developed. The investigation shows that the losses can be reduced by utilizing a multilevel topology for a 1 MW drive. This work is presented in [46]. The same reduction in losses is proven for a 2300V/ 3 MW drive.
Analytical expressions for the harmonic losses in 3-level converters have been developed for 2 different Carrier Based PWM schemes, presented in [56], [57] and [58]. Also Space Vector PWM are investigated and compared by simulations, in addition to 4- and 5-level Carrier Based PWM.
DC-bus balancing in both 3- and 5-level converters is discussed. Balancing in 3- level converters can be achieved by proper control. Balancing in 5-level converters can be achieved by proper arrangement of isolated DC-supplies.
One 40kW 3-level converter and one 5kW 5-level converter has been designed and built. Experimental verification of the analytical and simulated results is shown.
Cavanaugh, Curtis. "AN ADAPTIVE ELECTRONIC INTERFACE FOR GAS SENSORS." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020108-121219.
Full textCAVANAUGH, CURTIS C. An Adaptive Electronic Interface for Gas Sensors (Under the direction of H. Troy Nagle).This thesis focuses on the development of an adaptive electronic interface for gas sensors that are used in the NC State electronic nose. We present an adaptive electronic interface that allows for the accurate mapping of the sensor?s voltage output to sensor resistance profiles. The adaptive interface uses a linearized Wheatstone bridge in a constant current configuration. The balancing of the bridge and the adjustment of the subsequent gain stage is performed using programmable variable resistors. The programmable resistors are controlled by a LabVIEW® program. The same control program also determines and records all the resistor values in the interface circuit. The resistance of each sensor is accurately computed by LabVIEW® using the interface-circuit, resistor values, and the voltage output of the circuit. Compensating for sensor drift can be done in LabVIEW® by adjusting the programmable resistor values so that a zero-voltage output is produced during the reference cycle. By doing this zero adjustment between each ?sniff? of an odorant, the baseline drift can be minimized.A single channel of the adaptive electronic interface has been designed and tested. The interface can be calibrated so that it is 99% accurate when performing sensor resistance measurements.A new conducting polymer sensor chamber has also been designed and tested. The new radial flow sensor chamber was minimizes the dead volume in the chamber and also deliver the odorant to each sensor at the same time. Two operating modes were compared: continuous-flow and sniff-and-hold. Both modes gave good classification performance while testing four different coffee samples. Experimental testing indicates that sensor response is highly correlated with the sample flow rate. Future work to more fully characterize this correlation is recommended.
Du, Toit J. A. (Jacques Andre). "Development and analysis of a distributed control strategy for power electronic converters." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52761.
Full textENGLISH ABSTRACT: The dissertation presents an alternative approach to the control of power electronic converters. The conventional approach is to use a centralized controller with one or more measurement systems providing feedback. As converters become larger, in both power rating and complexity, a number of drawbacks to this approach emerge. The number of physical data paths increases and voltage isolation becomes a problem. This has an adverse effect on the manufacturability as well as the reliable operation of the system as a whole. An alternative is to use a distributed control approach, where a number of smaller integrated control and measurement units are used. These units communicate with the central controller via a serial daisy-chain communications link. The dissertation investigates the design of such a controller as well as the application of distributed control in a number of emerging converter topologies. It was shown that centralized control has its limitations in modem power electronics in terms of reliability, maintainability and manufacturability. A feasible distributed control strategy was proposed and implemented and the operation was verified in an experimental converter system.
AFRIKAANSE OPSOMMING: Die proefskrif ondersoek 'n alternatiewe manier om drywings omsetters te beheer. Huidiglik word die meerderheid van omsetters beheer vanaf 'n sentrale beheereenheid, wat dan stelsel data versamel vanaf een of meer meetstelsels. Soos die drywingsvermoë van die omsetters toeneem, raak spannings isolasie en die aantal beheerseine 'n probleem, wat nadelig is vir die betroubaarheid en vervaardigbaarheid van die stelsel. As 'n alternatief, kan 'n aantal kleiner beheereenhede en meetstelsels gebruik word. Die beheerders kommunikeer met mekaar, sowel as die hoof stelselbeheerder deur middel van 'n optiese vesel netwerk, verbind in 'n ring struktuur. Die proefskrif ondersoek die ontwerp van die beheerder en die toepassing van gedesentraliseerde beheer in 'n aantal nuwe omsetter topologië. Die studie toon dat sentrale beheer problematies kan raak soos die omsetters meer kompleks raak. Die studie bewys dat 'n stelsel suksesvol bedryf kan word deur gebruik te maak van gedesentraliseerde beheer deur dit in 'n praktiese opstelling toe te pas.
Valsalan, Rincy. "Electronic Water Heater." Thesis, Högskolan i Halmstad, Halmstad Embedded and Intelligent Systems Research (EIS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-37922.
Full textAhmadi, Teshnizi Amir Pouya, Marcus Hellström, Tom Bärnheim, and Hassan Soltani. "IoT Air Quality Sensor Array : Master's Programme in Electrical Engineering." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448142.
Full textNeff, Clayton. "Analysis of Printed Electronic Adhesion, Electrical, Mechanical, and Thermal Performance for Resilient Hybrid Electronics." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7551.
Full textWu, Yudong. "Simulation of graphene electronic devices." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1554/.
Full textyang, xiao yang. "Electronic Properties of Methyl-Terminated Germanane and Hydrogen-terminatedGermanane." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1502899689885614.
Full textOwadally, Muhammud Asaad. "Robust electronic circuit design using evolutionary and Taguchi methods." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/21761.
Full textIn engineering, there is a wide range of applications where genetic optimizers are used. Two genetic optimizers used in this thesis namely, Population Based Incremental Learning ( PBIL ) and Cross generational selection Heterogeneous crossover Cataclysmic mutation ( CHC ), are tested on a series of circuit problems to fmd if robust electronic circuits can be built from evolutionary methods. The evolutionary algorithms were used to search the space of discrete component values from a range of manufactured preferred values to obtain robust electronic circuits. Parasitic effects were also modelled in the simulation to provide for a more realistic circuit.
Al, Kzair Christian, Altin Januzi, and Andreas Blom. "Understanding the fundamentals of CPU architecture : Bachelor project in Electrical engineering." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353427.
Full textGeerdts, C. D. "SOFTWIRE : an interactive, computer-based system for enhancing learning in electrical engineering using simulation." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/8364.
Full textBarto, Taylor. "Design and Control of Electronic Motor Drives for Regenerative Robotics." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu150396313057516.
Full textDe, Wit Leon. "Flicker mitigation in industrial systems." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1994.
Full textThis thesis investigates the compensation of voltage flicker in an industrial environment. Industrial loads draw progressively less sinusoidal currents. These currents cause non-sinusoidal voltage drop over the line impedance, causing a distorted line voltage. The light output of incandescent electric lighting systems is quadratically proportional to the line voltage, and thus variations in the line voltage cause irritating variations in the output of such systems. Two tools to analyse flicker problems are developed: A USB data logger is built to log measured waveforms to computer hard disk. These data are analysed using a MATLAB implementation of the IEC-specified flicker meter. A converter-based flicker compensator is found to be the only compensator capable of compensating general flicker loads. Such a compensator is developed using the synchronous reference frame filtering technique. Several aspects of the compensator are dealt with in detail including selection of a current control strategy, calculation and implementation of the converter duty cycles and compensation of the various non-idealities in such a controller. Full compensation is contrasted to reactive compensation – the second option being less expensive but also less effective in the compensation of certain loads. The effectiveness of reactive compensation is found to be dependent not only on the type of load, but also on the type of line feeding the flicker load. Three industrial flicker loads are measured and analysed: a three-phase welder, a sawmill and a rock crusher. These loads are simulated, and the compensation proposed confirmed via these simulations. The compensation of the three-phase welder is tested using a hardware scale model. This verified the operation of the proposed flicker compensator in practice.
Shang, Alain. "Transceiver arrays for optically interconnected electronic systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37024.pdf.
Full textMahajan, Nikhil R. "System Protection for Power Electronic Building Block Based DC Distribution Systems." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-12052004-233822/.
Full textWang, Han Ph D. Massachusetts Institute of Technology. "Two-dimensional materials for electronic applications." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84899.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 205-232).
The successful isolation of graphene in 2004 has attracted great interest to search for potential applications of this unique material and other members of the two-dimensional materials family in electronics, optoelectronics and their interface with the biological systems. At this early stage of 2D materials research, many opportunities and challenges co-exist in this area. This thesis addresses the following issues which are crucial for 2D electronics to be successful, focusing on developing graphene for RF electronics and MoS2 for digital applications: (1) Development of some of the first graphene-based devices for high frequency applications; (2) Development of compact physical models for graphene transistors; and (3) Understanding the carrier transit delays in graphene transistors. In addition, this thesis proposes and experimentally demonstrates a completely new concept - Ambipolar Electronics - to take advantage of the unique properties of graphene for RF applications. Based on this new concept, a family of novel applications are developed that can significantly simplify the design of many fundamental building blocks in RF electronics, such as frequency multipliers, mixers and binary phase shift keying devices. In the last part of the thesis, the applications of other emerging 2D materials from the transition metal dichalcogenides family, such as molybdenum disulfide (MoS₂), is also explored for potential application in digital electronics, especially as a new material option for high performance flexible electronics. The future opportunities and potential challenges for the applications of the 2D materials family are also discussed.
by Han Wang.
Ph.D.
Liburd, Soyini (Soyini Denise) 1980. "An N-version electronic voting system." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28441.
Full textIncludes bibliographical references (p. 103-109).
The ballot battles of the 2000 US Presidential Election clearly indicate that existing voting technologies and processes are not sufficient to guarantee that every eligible voter is granted their right to vote and implicitly to have that vote counted, as per the fifteenth, nineteenth, twenty fourth and twenty sixth amendments to the US constitution [1-3]. Developing a voting system that is secure, correct, reliable and trustworthy is a significant challenge to current technology [3, 4]. The Secure Architecture for Voting Electronically (SAVE) demonstrates that N-version programming increases the reliability and security of its systems, and can be used to increase the trustworthiness of systems. Further, SAVE demonstrates how a viable practical approach to voting can be created using N-version programming. SAVE represents a significant contribution to voting technology research because of its design, and also because it demonstrates the benefits of N-version programming and introduces these benefits to the field of voting technology.
by Soyini D. Liburd.
M.Eng.
Cohen, Sharon B. "Auditing technology for electronic voting machines." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33119.
Full textIncludes bibliographical references (leaf 63).
Direct Recording Electronic (DRE) voting machine security has been a significant topic of contention ever since Diebold voting machine code turned up on a public Internet site in 2003 and computer scientists at Johns Hopkins University declared the machine "unsuitable for use in a general election." Since then, many people from computer scientists to politicians have begun to insist that DREs be equipped with a paper trail. A paper trail provides a paper printout for the voter to approve at the end of each voting session. Although there have been strong political efforts to place paper trails on DRE machines, there have not been any scientific studies to indicate that paper trails are effective audits. This work describes a user study done to compare paper trails to audio audits, a new proposal for DRE auditing. Participants in the study completed four elections on a voting machine with a paper trail and four elections on a machine with an audio trail. There were purposeful mistakes inserted into the audits on some of the machines. Results from the study indicated that participants were able to find almost 10 times as many errors in the audio audit then they were able to find in the paper trail. Voters' attitudes towards the paper audit were extremely apathetic, and voters did not spend much time reviewing their paper record. When asked which type of audit voters would prefer for their own county elections, almost all voters preferred the VVPAT. These results indicate that newer alternative audit technology holds great promise in delivering a safe and accurate audit and further that paper trails have some significant design obstacles that need to be overcome before they will be effective audits.
by Sharon B. Cohen.
M.Eng.and S.B.
Koen, Douglas B. (Douglas Branch). "Automated restructuring of an electronic newspaper." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/34337.
Full textRubin, Jeremy Lloyd. "Decentralized utilization incentives in electronic cash." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105964.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 109-113).
Many mechanisms exist in centralized systems that incentivize resource utilization. For example, central governments use inflation for many reasons, but a common justification for inflation in practice is as a means to incentivize resource utilization. Incentives to utilize resource may stimulate economic growth. However, the asymmetry of economic control and potential abuses of power implicit in centralized systems may be undesirable. An electronic cash design may be able to create resource utilization incentives via decentralized mechanisms. Decentralized mechanisms may be economically sustainable without centralized and potentially coercive forces. We propose Hourglass, a novel electronic cash design that provides a decentralized mechanism to encourage utilization via expiration dates. Constructed in this way, decentralized utilization incentives may have less potential for coercive abuses than more centralized methods, but may be similarly effective in their ability to incentivize utilization. We present the Hourglass system at multiple levels of detail: a design overview, a minimal kernel framework, a series of descriptive refinements, and a concrete implementation as a fork of Bitcoin (a popular electronic cash protocol in common use). We also present several potential applications of Hourglass, such as renewable resource markets, spectrum allocation, stock issuance, and currency.
by Jeremy Lloyd Rubin.
M. Eng.
Bridge, David Richard. "Aspects of electronic device packaging." Thesis, University of Warwick, 1986. http://wrap.warwick.ac.uk/58807/.
Full textMitchley, Ryan. "Evaluation of selected subspace tracking algorithms for direction finding." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/442.
Full textGalbraith, A. S. G. "Estimation of Synchronous Generator Parameters using Time-domain Responses." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1663.
Full textPower system stability simulations are of growing importance for studying the operational integrity of modern power systems, especially in developing economies where generating and transmission capacity lead the demand by relatively small margins. The relevant model topologies, i.e. for synchronous generators, automatic voltage regulators (AVR) and governor control systems, and the simulation software tools are well established. The MATLAB® Power System Blockset provides engineers with a versatile power system stability simulation environment, particularly where the focus is on individual units or small systems. In comparison with dedicated power system simulation tools such as DIgSILENT®, the MATLAB® environment features a superior set of advanced data processing and data analysis features. This includes features such as optimisation and parameter estimation functions. The main aim of this project is to make use of the MATLAB® package in a bid to test an alternative platform with which to estimate the synchronous machine parameters. Conditioning of field data can delay the process considerably, thus the secondary task of this thesis is to solve this issue by ensuring that only one platform is needed for the entire process starting in the field and ending in the modelling and parameter estimation environment within MATLAB®. In closing, the following points summarise the essential aims of this project: • An application using MATLAB® Script must be created that is responsible for importing and processing the data, so it is suitable for analysis purposes. The processing could include cropping, scaling and filtering of data. • Once the data has been imported it must be used with appropriate models to estimate for machine parameters. This will require the use of the Power Systems Blockset. The actual estimation process also requires the creation of an effective cost function, thus a number of different scenarios will have to be investigated before a solution can be found.
Sumsurooah, Sharmila. "Robust stability analysis of power electronic systems." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/37829/.
Full textBarrios, Andres J. "Nonlinear quantum transport in low-dimensional electronic devices." FIU Digital Commons, 2002. http://digitalcommons.fiu.edu/etd/1414.
Full textNie, Xin 1969. "Graphic user interface for power electronic research facility." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20511.
Full textThe user interface manages the data transfer between the hardware and user and allows the user to change the hardware settings via interactive dialogs. It also displays the current parameters running on the hardware, thus provides the user with a more convenient and efficient way of monitor the performance of the multi-converter research facility.
Germain, François. "A nonlinear analysis framework for electronic synthesizer effects." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104845.
Full textCette thèse présente une étude théorique et expérimentale du comportement nonlinéaire des effets de synthétiseurs analogiques. Elle vise à évaluer et compléter les recherches actuelles sur la modélisation des systèmes non-linéaires, à la fois dans le domaine de la technologie de la musique et en dehors. Les cas des effets à une ou plusieurs entrées sont examinés. Pour ce faire, nous présentons d'abord une analyse électronique des circuits de plusieurs exemples usuels d'effets analogiques tels que le filtre passe-bas de Moog ou le modulateur en anneau de Bode. Les équations régissant chaque système en sont dérivées. Nous discutons ensuite le résultat d'expériences menées sur ces systèmes pour extraire une caractérisation qualitative de la distorsion présente dans le rapport entrée-sortie du système. Dans un second temps, nous examinons les méthodes de modélisation des systèmes non-linéaires à une entrée trouvées dans la littérature, et nous explorons les possibilités d'extension de ces techniques aux systèmes à plusieurs entrées. Deux approches de modélisation sont abordées. L'approche boîte noire vise à modéliser la fonction de transfert entrée-sortie du système aussi fidèlement que possible sans hypothèse sur la structure du système. L'approche de la modélisation du circuit utilise quant à elle la connaissance du comportement des composants électroniques pour extraire une fonction de transfert à partir du circuit (connu) du système. Les résultats associés aux deux approches sont comparés à nos expériences pour évaluer leur performance, et identifier des lacunes et, quand c'est possible, des opportunités d'amélioration de ces méthodes.
Escobar-Mejia, Andres. "Indirect Matrix Converter as Standard Power Electronic Interface." Thesis, University of Arkansas, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3667722.
Full textThe increase in the penetration levels of distributed generation in the modern power grid and its importance in future energy systems have accelerated the interest of developing new power electronic interfaces for the energy conversion process. The feasibility of applying the indirect matrix converter as the standard power electronic interface for applications with power ratings from several kW to few MW is addressed in this dissertation. Special attention is given to those applications where space dominates the power electronic requirements. The main motivation for using the indirect matrix converter is that eliminates the energy storage component in the way of a dc-link capacitor for the energy conversion process. This contributes to reduce size and weight, and potentially, increase reliability of the power electronic interface. Two main new contributions are presented. First, a new power electronic interface that allows the connection of two ac power grids through a medium- or high-voltage dc system is proposed. The new topology contemplates the use of two high-voltage dc-link converters based on the modular multilevel converter, two indirect matrix converters and two medium-frequency transformers. Second, a new sensorless control technique working in the d – q reference is developed. The controller is used to interface a distributed generation unit to the power grid when the indirect matrix converter is used as the power electronic interface. The design and performance of the proposed power electronic interface is validated through time-domain simulations and a laboratory prototype is built to experimentally validate the sensorless controller.
Jiang, Yang. "Clock-jitter insensitive circuit techniques in continuous-time sigma-delta modulators." Thesis, University of Macau, 2012. http://umaclib3.umac.mo/record=b2590641.
Full textRisemark, Eriksson Martin. "Environmental stress of electrical machine winding insulation." Thesis, Uppsala universitet, Elektricitetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326711.
Full textVoigt, Dewald. "Computational investigation of a crossed slot cavity-backed array antenna." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2659.
Full textThis thesis investigates a computational model of an electronically steered antenna array. It focuses on a simple element comprising an S-shaped, crossed, cylindrical cavity-backed slot antenna. An unusual aspect of the element is the addition of a top hat, which contributes to the low scanning ability of the array. The objective was to confirm this contribution of the top hat. During the investigation, the computation code Feko was validated for slot analysis through consideration of the basic properties of a dipole and slot and how they related to each other. Various alternative models were evaluated, before a final accurate model was modelled in Feko, to find possible equivalent models. The final model, which implemented the use of Feko as release 5, was the only one that achieved successful results. The results showed that the top hat does play an important role in the steering of the beam. The mechanism through which this occurs was identified. The results that where obtained indicated that there may be more effective elements than the cylindrical element and the identification of this is proposed as a field for further study.
Varzandeh, Navid. "New immobilizer concept based on Scania’s electrical platform." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29180.
Full textYao, James Chung-Yo. "Leaders for Manufacturing Program electronic mail network." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/61055.
Full textBagwell, Philip F. (Philip Frederick). "Quantum mechanical transport in submicron electronic devices." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/44264.
Full textZhang, Xu Ph D. Massachusetts Institute of Technology. "Two-dimensional crystals : spectroscopy and electronic applications." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112036.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 159-177).
The success in creating atomically thin and mechanically robust two-dimensional (2D) crystals, starting with graphene, has unveiled new possibilities for next generation of ultrafast and ubiquitous electronics. One critical distinction between 2D crystals and 3D crystals is that 2D crystals are all-surface materials. Therefore, it is essential to understand how 2D materials interact with their environments and how this interaction impacts their electronic properties. From a practical perspective, it also provides us with a unique tool to tailor the electronic properties of 2D materials through surface functionalization. In the first half of this thesis, a suite of X-ray techniques is used to investigate how the surface functionalizing dopants will impact the electronic and chemical states of graphene. Based on this study, we develop an effective and non-invasive doping method for graphene through plasma-based chlorination. In order to make system-level 2D electronics successful, a flexible and ubiquitous energy harvesting solution is indispensable. Therefore, the second part of this thesis is dedicated to the development of a MoS₂ 2H-1T phase heterojunction-based GHz flexible rectifier as an enabling component for wireless energy harvester. It is the first flexible rectifier operating up to the X-band and it covers most of the unlicensed industrial, scientific and medical (ISM) radio band, including the Wi-Fi channels. By integrating this rectifier with an antenna, the MoS₂-enabled rectenna successfully demonstrates direct energy harvesting of electromagnetic (EM) radiation in the Wi-Fi band and lights up a commercial light-emitting diode (LED) with zero external bias (battery-free). Moreover, our MoS₂ rectifier also realizes successful frequency conversion as a mixer beyond 10 GHz on flexible substrates. This work provides a universal energy harvesting building block that can be integrated with various wearable electronic systems and paves the way towards using the existing Wi-Fi infrastructure as an energy hotspot for wireless charging.
by Xu Zhang.
Ph. D.
Tassoudji, Mohammad Ali. "Electromagnetic interference in electronic circuits and systems." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35392.
Full textIncludes bibliographical references (p. 191-198).
by Mohammad Ali Tassoudji.
Ph.D.
Moy, Melanie 1979. "A secure architecture for electronic check processing." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28446.
Full textIncludes bibliographical references (leaves 49-51).
Traditional paper checks have been estimated to cost US banks over $2.1 billion dollars a year to process [1]. Much of the cost is due to the time and fees related to human intervention and the physical transport of a check. Gupta and Palacios [15] have defined a web-based check processing mechanism; this paper extends the framework they have developed and defines a cryptographic protocol for the transmission of digital checks using cryptographic building blocks like public key encryption and digital signatures.
by Melanie Moy.
M.Eng.
Nickel, Jacob. "Development of an electronic lung airway atlas." Thesis, University of Iowa, 2008. http://ir.uiowa.edu/etd/14.
Full textEnohnyaket, Mathias. "Electromagnetic characterization of power electronic systems." Doctoral thesis, Luleå tekniska universitet, EISLAB, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17800.
Full textGodkänd; 2010; 20100826 (mathen); DISPUTATION Ämnesområde: Industriell elektronik/Industrial Electronics Opponent: Professor Mats Alaküla, Lund University and Volvo Car AB Ordförande: Professor Jerker Delsing, Luleå tekniska universitet Tid: Torsdag den 30 september 2010, kl 09.30 Plats: A1514 Demostudion, Luleå tekniska universitet
EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem
Delport, Pierre. "Optimisation of UHF radio SCADA systems for electrical distribution networks." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1905.
Full textThis thesis presents the results of an investigation to establish methods to improve the performance of area radio based communication systems for Supervisory Control and Data Acquisition (SCADA) systems. The considerable scale on which an area radio network is used as a telecommunication network is quite unique to South Africa due to a lack of high bandwidth telecommunication systems in rural areas. Research was done to establish Key Performance Indicators (KPIs) to measure the performance of the area radio telecommunication systems. Two KPIs were chosen, namely Remote Terminal Unit (RTU) availability and Control Success Rate (CSR). These KPIs were trended over a three-year period to measure the effectiveness of measures taken to improve the systems. Two measures were implemented, namely to change the RTU radios, antennas and coaxial feeder cables and to redesign the communication systems in such a way to restrict multiple RTU protocols on the same area radio telecommunication network. The installation of new digital radios together with low loss coaxial cable and specific antennas improved the RTU availability from 96.87 % for the year 2002 to 99.17 % for the year 2004, which realised in an increase of 2.83 % for 432 installed RTUs. This measure, however, did not influence the CSR. The implementation of the newly designed communication networks had a significant influence on the control success rate of the SCADA systems and the KPI increased from 77.65 % for the year 2002 to 78.76 % for the year 2003 and 80.88 % for the year 2004. A drastic increase in performance was observed after the restriction of multiple RTU protocols on the same network during May 2004, where the value for twelve months prior to September 2005 was measured at 84.38 %. The utilisation of area radio telecommunication networks was measured for two operational networks and it was found to be well within the specifications of international accepted standards. One of these networks comprised of three repeaters and 84 installed RTUs and an average utilisation of 17 % and a peak utilisation of 25 % was measured. The other network had an installed base of 4 repeaters and 15 installed RTUs’s and an average utilisation of 3 % and a peak utilisation of 8 % was measured. This compares favourable with the IEEE standard 999-1992 [20], which recommends a channel utilisation of between 40 % and 60 %. Keywords : Key performance indicators, Radio telecommunication networks, Remote terminal unit
Brady, Richard. "A Cross Platform Framework for Software Defined Radio." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/2056.
Full textSoftware defined radios (SDRs) implement in software those parts of a radio which have traditionally been implemented in analogue hardware. We explain the importance of this definition and introduce reconfigurability and portability as two further goals. Reconfigurabilty is a property of the SDR platform, which may be a microprocessor, configurable hardware device, or combination of the two. We demonstrate that the field-programmable gate array is suficient for the implementation of practical SDR systems. Portability, on the other hand, is a property of the modulation and demodulation software, also known as waveform specification software. We evaluate techniques for achieving portability and show that waveforms can be specified in a generic form suitable for the autogeneration of implementations targetting both microprocessor- and FPGA-based architectures. The generated code is in C++ and VHDL respectively, and the tools used include formal models of computation and the XSLT language.
Blaauw, Deon. "Flight control system for a variable stability blended-wing-body unmanned aerial vehicle." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2297.
Full textThis thesis presents the analysis, design, simulation and practical implementation of a novel control system for a variable stability blended-wing-body unmanned aerial vehicle. The aircraft has a moveable centre of mass that allows it to operate in an aerodynamically optimised minimum drag configuration during cruise flight. The primary purpose of the control system is thus to regain nominal static stability for all centre of mass positions, and then to further regulate motion variables for autonomous way point navigation. A thorough analysis of the parameters affected by the varying centre of mass position leads to the identification of the main control problem. It is shown that a recently published acceleration based control methodology can be used with minor modification to elegantly solve the variable stability control problem. After providing the details of the control system design, the customised avionics used for their practical implementation are presented. The results of extensive hardware in the loop simulations verify the functionality of the controllers. Finally, flight test results illustrate the practical success of the autopilot and clearly show how the control system is capable of controlling the variable stability aircraft at centre of mass locations where a human pilot could not.
Jones, Jeffrey Alun. "Electronic reliability prediction : a study over 25 years." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/1991/.
Full textMa, Yuefei. "Analysis of programmable molecular electronic systems." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5997.
Full textSchneck, Jude Robert. "Femtosecond electronic dephasing and population relaxation of some novel semiconducting materials." Thesis, Boston University, 2012. https://hdl.handle.net/2144/34692.
Full textPLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
The dissipation of energy by excited carriers in semiconductors is crucial to device development. In particular, the carrier relaxation mechanisms are strongly modified by the degree of disorder introduced into the lattice via the growth process. The pump probe spectroscopic technique is ideally suited to monitor the energy dissipation process and elucidate the relaxation mechanisms contributing to the carrier decay. Additionally, phase breaking interactions of optical transitions, as measured via the photon echo spectroscopic technique, provides insight into the different homogeneous relaxation mechanisms contributing to the optical resonance. When compared to high quality semiconducting materials, the fundamental homogeneous relaxation mechanisms depend strongly on the disorder inherent in the material. The photon echo technique is ideal for quantifying the strength of these interactions. Femtosecond pump-probe responses of a GaN thin film excited above and below the UV band gap were measured to determine the kinetic relaxation pathways of carriers. A number of fluence dependent decay processes were identified, including carrier-carrier scattering, exciton decay, trapping to defect states, and hole state recovery. The characteristic timescales of these mechanisms ranged from <50 fs to >600 ps. In other measurements on GaN, two-pulse photon echoes due to the strongly dipole coupled excitons were observed as a function of temperature (1 0 - 295K). A biexponential decay of the dephasing rate was found from these measurements and attributed to free and bound excitons. The dynamics of the E22 transition of (6,5) single walled carbon nanotubes was studied over a range of fluences via pump-probe spectroscopy. A fluence dependent dephasing rate was deduced from an analysis of the pump-probe signal intensity at a fixed short delay time allowing an effective cross section for exciton-exciton interactions to be determined. The relaxation kinetics of optically excited E22 excitons was revealed by pump fluence dependent fits to the observed pump-probe responses. The model includes both Auger recombination from the E11 and E22 states due to exciton-exciton annihilation and a stretched exponential decay from E11 to the valence band. E11 and E22 diffusion coefficients and the defect density were determined from this analysis.
2031-01-01