Dissertations / Theses on the topic 'Switching systems'
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Jomah, Adel M. "Instability in switching systems." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322593.
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Sime, Julie-Ann. "Model switching in intelligent training systems." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1396.
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Ghimire, Manoj. "Switching Neural Network Systems for Nonlinear Tracking." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright154708422929052.
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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.
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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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Chang, Michael. "Adaptive switching control applied to multivariable systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27888.pdf.
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Aghdam, Amir G. "Decentralized control of systems using switching methods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/NQ53722.pdf.
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Einarsson, Valur. "Model checking methods for mode switching systems /." Linköping : Univ, 2000. http://www.bibl.liu.se/liupubl/disp/disp2000/tek652s.htm.
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Locane, Elina [Verfasser]. "Switching processes in mesoscopic systems / Elina Locane." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/115576112X/34.
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Strawser, Richard E. "MEMS Electrostatic Switching Technology for Microwave Systems." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin974746046.
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Lu, Yueyun. "Switching Stabilization of Continuous-Time Switched Systems." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1479201964449478.
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Sathyan, Saju. "All Optical Switching Architectures." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-253.
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In communication systems, the need for high bandwidth interconnects and
efficient distribution of large amount of data is very essential. This thesis work
addresses all-optical packet switching issues in the field of reconfigurable optical
interconnection networks for high performance embedded systems. The recent
research conducted at the Halmstad University, on high performance embedded
systems, focuses on the optical interconnection techniques to achieve ultra high
throughputs and reconfigurability at the system level.
Recent research in the field of optical interconnection networks for applications
like switches and routers for data and telecommunication industry and parallel
computing architectures for embedded signal processing use optical to electrical
conversion to switch packets. This conversion scales down the enormous bandwidth
capacity of the optical communication channels to electronic processing rates. To
maintain the high throughputs all over the interconnection networks, the optical
packets need to be maintained in optical state and switched to different part of the
interconnection network. To achieve this goal, all-optical packet switching
architectures are studied. The study is concluded with a positive outlook towards alloptical
switching technologies, and it will play a very important role in the near
future in the field of optical communication, telecommunication and embedded
systems.
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Tohme, Philip Edward. "Optical switching and its application in Sonet-based transmission systems." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10242009-020314/.
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Kaisare, Niket S. "Modeling, Analysis and Control of Nonlinear Switching Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6976.
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The first part of this two-part thesis examines the reverse-flow operation of auto-thermal methane reforming in a microreactor. A theoretical study is undertaken to explain the physical origins of the experimentally observed improvements in the performance of the reverse-flow operation compared to the unidirectional operation. First, a scaling analysis is presented to understand the effect of various time scales existing within the microreactor, and to obtain guidelines for the optimal reverse-flow operation. Then, the effect of kinetic parameters, transport properties, reactor design and operating conditions on the reactor operation is parametrically studied through numerical simulations. The reverse-flow operation is shown to be more robust than the unidirectional operation with respect to both optimal operating conditions as well as variations in hydrogen throughput requirements. A rational scheme for improved catalyst placement in the microreactor, which exploits the spatial temperature profiles in the reactor, is also presented. Finally, a design modification of the microreactor called "opposed-flow" reactor, which retains the performance benefits of the reverse-flow operation without requiring the input / output port switching, is suggested.
In the second part of this thesis, a novel simulation-based Approximate Dynamic Programming (ADP) framework is presented for optimal control of switching between multiple metabolic states in a microbial bioreactor. The cybernetic modeling framework is used to capture these cellular metabolic switches. Model Predictive Control, one of the most popular advanced control methods, is able to drive the reactor to the desired steady state. However, the nonlinearity and switching nature of the system cause computational and performance problems with MPC. The proposed ADP has an advantage over MPC, as the closed-loop optimal policy is computed offline in the form of so-called value or cost-to-go function. Through the use of an approximation of the value function, the infinite horizon problem is converted into an equivalent single-stage problem, which can be solved online. Various issues in implementation of ADP are also addressed.
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Nguyen, Canh Quang Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Switching robust adaptive control in nonlinear mechanical systems." Awarded by:University of New South Wales. School of Mechanical & Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/24318.
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This work describes analysis, design, and implementation of a novel switching robust adaptive control (SRAC) method for nonlinear systems. The proposed method takes advantage of both adaptive control (AC) and robust control (RC) methods. SRAC employs one of the methods when this method is advantageous and switches to the other method when the other one becomes the preferred choice. To this end, RC is used to deal with transient effects caused by uncertainties and disturbances. The system switches over to AC for good steady state performance when certain switching criteria are satisfied. If external disturbances become dominant or new uncertainties are introduced while AC is active, the system will switch back to RC. In this manner, the switching process between AC and RC will continue to take place guaranteeing improved performance, robustness, and accuracy for the entire operation of the system. The novel idea behind the proposed method is a smart novel mechanism of bi-directional switching between RC and AC. In this mechanism, the involvement of estimators and switching rules play a decisive part in guaranteeing the smooth switching and the stability of the system. The implementation and design issues of the novel method were first evaluated by simulation on a mass spring system and then on a robot manipulator system. To control these systems with satisfactory performance, nonlinearities and uncertainties have been properly analysed and embedded into models and control algorithms. Simulation results showed the superior performance of the proposed method compared with other control methods. The experimental validation of the proposed method was conducted on a Puma 560 robot manipulator system which was established by joints 2 and 3 of the robot. Extensive comparative experimental results have validated the efficacy and superior performance of the proposed SRAC method over other control methods in the face of uncertainties and disturbances. As part of this work, a comprehensive dynamic model of robotic manipulator in the presence of joint motors, gravitational forces, friction forces and payload has been developed using MAPLE. A systematic design framework for the SRAC method has also been developed.
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Hurth, Tobias. "Invariant densities for dynamical systems with random switching." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52274.
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We studied invariant measures and invariant densities for dynamical systems with random switching (switching systems, in short). These switching systems can be described by a two-component Markov process whose first component is a stochastic process on a finite-dimensional smooth manifold and whose second component is a stochastic process on a finite collection of smooth vector fields that are defined on the manifold. We identified sufficient conditions for uniqueness and absolute continuity of the invariant measure associated to this Markov process. These conditions consist of a Hoermander-type hypoellipticity condition and a recurrence condition. In the case where the manifold is the real line or a subset of the real line, we studied regularity properties of the invariant densities of absolutely continuous invariant measures. We showed that invariant densities are smooth away from critical points of the vector fields. Assuming in addition that the vector fields are analytic, we derived the asymptotically dominant term for invariant densities at critical points.
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Alias, Qais M. "Single-pole switching schemes for EHV transmission systems." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379059.
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Karalis, Paschalis. "Stability and stabilisation of switching and hybrid dissipative systems." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/stability-and-stabilisation-of-switching-and-hybrid-dissipative-systems(3e6ee880-e59a-49ed-a2f2-1612df85557f).html.
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A method is proposed to infer stability properties for non-linear switching under continuous state feedback. Continuous-time systems which are dissipative in the multiple storage function sense are considered. A partition of the state space, induced by the cross-supply rates and the feedback function, is used to derive a restriction on switching. Then, conditions are proposed, under which, systems controlled by the feedback function and switching according to the rule are stable. In particular, Lyapunov and asymptotic stability are proved, both in a local and in a global context. Further, it is shown that the approach can be extended when one uses multiple controllers, and, therefore, is able to construct multiple partitions; conditions for this case are also presented. Finally, it is shown that, for the switching families that satisfy the switching rule posited by the results, one is able to find elements (that is, stabilising switching laws for the system) which are non-Zeno. Additional rule-sets that allow this are provided. It is argued that the conditions proposed here are easier to verify and apply, and that they offer additional flexibility when compared to those proposed by other approaches in the literature. The same infrastructure is used in the study of hybrid systems. For a general class of non-linear hybrid systems, a new property is proposed, that retains some of the properties of dissipativity, but it differs from it, crucially in the fact that it is not purely input-output. For systems having this property, it is shown that the partition used in the switching case can also be used. This, along with a set of conditions allows for the characterisation of the system behaviour in two scenaria. First, when the continuous behaviours and the jumping scheme act co-operatively, leading the system to lower energy levels (from the dissipativity point of view). Second, when the continuous behaviours are allowed to increase the stored energy, but the jumping is able to 6 compensate this increase. In the first case, it is shown that the equilibrium point under study is stable; in the second, it is shown that the system exhibits a type of attractivity, and, under additional conditions, it is asymptotically stable. Besides stability, a collection of stabilisation results are given for the case of dissipative switching systems. It is shown that one may design state feedback functions (controllers) with the objective that they satisfy the conditions of the stability theorems in this work. Then, systems under the designed controllers are shown to be stable, provided that the switching adheres to a specific switching rule. This problem is approached using a variety of tools taken from analysis, multi-valued functions and the space of non-switching stabilisation. In addition to the main results, an extensive overview of the literature in the area of switching and hybrid systems is offered, with emphasis on the topics of stability and dissipativity. Finally, a collection of numerical examples are given, validating the results presented here.
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Ng, Chi-kwong, and 吳志光. "Location management and level switching schemes in multitier mobile communication systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B30168661.
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Han, Qiwei. "Essays on Consumer Switching and Search Behavior." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/897.
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As recommender systems have increasingly become prevalent to guide consumers to find their desired products in many industries, understanding the impact of recommender systems on consumer choices is critical to the business performance and raises important policy implications. In this thesis, we examine the role of different recommendation schemes, spanning from interpersonal recommendations in social environment given by peers to product display recommendations in physical shopping environment given by sellers on consumers’ switching and search behavior in two distinct case studies. In the first study, we look at the effect of peer recommendations on subscriber churn in a large mobile network. We find that consumers’ propensity to churn increases with the number of friends that churn and in particular with the number of strong friends that churn. In the second study, we implement an in-vivo randomized field experiment to measure the effect of product display recommendations as book placement on shopper behavior in a physical bookstore. We leverage video tracking technologies to monitor how shoppers respond to random book placement, which induces random search costs. We find that books recommended at the edge of the table are more likely to be picked and taken than those placed at the center of the table. More interestingly, we also find that conditional on being picked, shoppers are equally likely to take books placed at the edge and at the center of the table, suggesting that display recommendations positively affect consumer choice mainly through its effect on the search process and not through its effect on the consideration process. Therefore, we empirically show that provision of recommendations, although in different schemes, may generally help to reduce consumers’ search costs in product or service discovery process, relative to what they would do without such an intervention. Moreover, we perform a comparative analysis between offline and online applications of recommender systems to systematically investigate the current practices, future prospects and policy perspectives when applying recommender systems in physical retailing. All these issues highlight opportunities for physical retailers to design, implement and evaluate their recommender systems that offer convenience benefits and appropriate protection to consumers.
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Lau, Siu Lik. "Reliability of optical crossconnect systems /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20LAUS.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 73-76). Also available in electronic version. Access restricted to campus users.
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Yildirim, Recep Ali. "Mmse Based Iterative Turbo Equalization For Antenna Switching Systems." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612480/index.pdf.
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In this thesis, we study the performance of an antenna switching (AS) system in comparison to an Alamouti coded system. We analyze the outage probabilities and propose minimum mean-squared error based iterative equalizers for both systems. We see from the outage probability analysis of both systems that the AS system may achieve the same diversity order of the Alamouti coded scheme contingent on the transmission rate and constellation size. In the proposed receiver, MMSE equalization and channel decoding are jointly carried out in an iterative fashion. We use both hard and soft decision channel decoders in our simulations. It is observed that the Alamouti based scheme performs better when the channel state information is perfect. The Alamouti scheme also performs better than the AS scheme when the channel state information is imperfect in hard decision channel decoder case and a random interleaver is used. On the other hand, if a random interleaver is not used, AS scheme performs remarkably better than the Alamouti scheme in hard decision channel decoder case. In a soft decision channel decoder case, when the channel state information is imperfect, the AS scheme performs approximately a 2 dB better than the Alamouti scheme. Moreover, there is approximately a 3 dB performance gain if a soft decision channel decoder is used instead of hard decision.
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Khattab, Tamer. "Optical Code Division Multiplexing for sub-wavelength switching systems." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31083.
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Optical Code Division Multiplexing (OCDMA) is a method used to enable simultaneous transmission of multiple optical data flows over the same fiber using the same wavelength. In OCDMA, isolation between different data flows is achieved using a set of uncorrelated, or loosely correlated, spreading codes to encode the transmitted signal and decode it at the receiver side. The process of encoding and decoding is performed entirely in the optical domain without the need for optical-to-electrical-to-optical conversion. This increases the granularity of traffic isolation in the optical domain while maintaining higher speed switching because of the all-optical encoding/decoding capability. Although code division multiplexing is a well established technique in wireless transmission where all processing of data and switching are performed electronically, there are many challenges in applying this scheme in the optical domain mainly due to the different characteristics of the medium and the fact that negative-valued signals are not easy to produce.
This thesis has three main objectives: to deploy OCDMA as a switching mechanism at the sub-wavelength level in order to increase the granularity of traffic isolation in all-optical core switching, to design new mechanisms that enhance the performance of OCDMA as a multiplexing method over long-haul optical fiber transmissions, and to
model the performance of OCDMA based switching and multiplexing mechanisms.
All-optical switching at the core of the network provides very high speed switching. However, it suffers from low utilization or lack of quality of service guarantees due to lack of fine granularity traffic isolation. This thesis presents an optical network architecture called Optical Code Labeled Generalized Multi-Protocol Label Switching (OC-GMPLS), which utilizes OCDMA as a switching mechanism in backbone GMPLS networks. OC-GMPLS uses OCDMA as an all-optical labeling space in GMPLS switching in order to achieve finer granularity switching at the all-optical network core.
The deployment of OC-GMPLS networks mandates performance modeling to show its advantages and to enable tuning of the new network parameters so that performance can be optimized. In this thesis we present an analytical model for the throughput and switching capacity of OC-GMPLS networks. Using our model, we show how to find optimal operating points for OC-GMPLS networks based on physical layer and network layer parameters.
The performance of OC-GMPLS networks depends on the performance of OCDMA transmission, which is affected by the modulation method and the optical spreading codes properties. In order to enhance the performance of OC-GMPLS networks, we take two different approaches. The first approach is based on proposing a modulation mechanism that enhances the communication reliability while maintaining low bit error rate for OCDMA transmissions. Our Chip-Level Modulated Binary Pulse Position Modulation (CLM-BPPM) scheme provides a simple to implement (in the all-optical domain) yet a
very powerful physical layer method for sending multiple optical flows using OCDMA while maintaining the Bit Error Rate (BER) due to Multiple Access Interference (MAI) effects between these flows at a low level of about 10⁻¹² for 10 simultaneous users. Our method provides a better capability in terms of clock recovery and user activity detection while achieving error rates in the range of those provided by On-Off Keying (OOK).
Performance of OCDMA transmission depends to a great extent on the efficiency of the codes used to perform the multiplexing. In order to tackle this side, we investigate the problem of Optical Orthogonal Code (OOC) design by proposing a method called Rejected Delays Reuse (RDR) for constructing OOCs using an element-by-element based greedy algorithm. We show that our method provides a computationally less complex algorithm for designing OOCs, which makes it more practical. Our analysis and simulation results show that OOCs designed using the RDR greedy method are also higher in multiplexing efficiency than OOCs designed using classical element-by-element constructions. This is because RDR designed OOCs possesses smaller code lengths for the same code cardinality and weight than their counterpart classical element-by-element greedy designed codes.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Hung, Tsai-Pi. "High efficiency switching-mode amplifiers for wireless communication systems." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3291921.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed March 18, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Leonessa, Alexander. "Hierarchical robust nonlinear switching control design for propulsion systems." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11997.
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Chwee, Ng Kim. "Switching control systems and their design via genetic algorithms." Thesis, University of Glasgow, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361268.
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Takahashi, Satoshi Ph D. Massachusetts Institute of Technology. "Integrated optical switching using titanium nitride micro electromechanical systems." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35645.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. [116]-[127]).
This thesis reports an integrated optical wavelength specific switching device for applications in optical integrated circuits (OICs) based on micro electromechanical systems (MEMS). The device consists of a ring resonator add-drop filter and a conductive MEMS bridge which is actuated by electrostatic force. Introducing conductive material into the electromagnetic evanescent field of the ring waveguide results in loss in the propagating light within, disabling the resonance and the filtering capabilities of the ring resonator. Therefore, by actuating the MEMS bridge in and out of the waveguide's evanescent field, the filter can be toggled between the on and off states. One large problem that must be faced when fabricating and actuating a MEMS cantilever or bridge structure for this type of device is the residual stress that may deflect the structure in an undesired way. This is because the vertical displacement of the structure is crucial. In order to solve this problem, this thesis is based on the use of titanium nitride (TiN) as structural material for the bridge. Titanium nitride has very attractive mechanical properties as well as good conductivity, which makes it an ideal structural material for electrostatically actuated devices.
(cont.) Moreover, the residual stress within the material can be relieved by proper control of deposition conditions and/or post processing. This thesis focuses on the post process annealing of titanium nitride in order to eliminate the residual stress in the structure and obtain a fiat bridge profile. Titanium nitride MEMS bridge structures were fabricated and tested. Their deflection from a flat state and stress was measured and characterized, and a structure with minimal residual stress was successfully fabricated. The actuation of the MEMS bridge is also demonstrated, and its characteristics are analyzed. Also discussed is the possibility of extending the design of the MEMS switch to implement the three-electrode ultra-fast strain-induced switching and MEMS wavelength tuning of an integrated optical filter. A realistic design of these devices is proposed in context with the requirements imposed by the optical telecommunication industry, and fabrication methods are considered. Simulations have been conducted using finite element analysis and mode solving to establish the feasibility of these designs.
y Satoshi Takahashi.
S.M.
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Radu, Cosmin. "Study of Magnetization Switching in Coupled Magnetic Nanostructured Systems." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/894.
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A study of magnetization dynamics experiments in nanostructured materials using the rf susceptibility tunnel diode oscillator (TDO) method is presented along with a extensive theoretical analysis. An original, computer controlled experimental setup that measures the change in susceptibility with the variation in external magnetic field and sample temperature was constructed. The TDO-based experiment design and construction is explained in detail, showing all the elements of originality. This experimental technique has proven reliable for characterizing samples with uncoupled magnetic structure and various magnetic anisotropies like: CrO2 , FeCo/IrMn and Co/SiO2 thin films. The TDO was subsequently used to explore the magnetization switching in coupled magnetic systems, like synthetic antiferromagnet (SAF) structures. Magnetoresistive random access memory (MRAM) is an important example of devices where the use of SAF structure is essential. To support the understanding of the SAF magnetic behavior, its configuration and application are reviewed and more details are provided in an appendix. Current problems in increasing the scalability and decreasing the error rate of MRAM devices are closely connected to the switching properties of the SAF structures. Several theoretical studies that were devoted to the understanding of the concepts of SAF critical curve are reviewed. As one can notice, there was no experimental determination of SAF critical curve, due to the difficulties in characterizing a magnetic coupled structure. Depending of the coupling strength between the two ferromagnetic layers, on the SAF critical curve one distinguishes several new features, inexistent in the case of uncoupled systems. Knowing the configuration of the SAF critical curve is of great importance in order to control its switching characteristics. For the first time a method of experimentally recording the critical curve for SAF is proposed in this work. In order to overcome technological limitations, a new way of recording the critical curve by using an additional magnetic bias field was explored.
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Oh, Sang Min. "Switching linear dynamic systems with higher-order temporal structure." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29698.
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Thesis (Ph.D)--Computing, Georgia Institute of Technology, 2010.Committee Chair: Dellaert, Frank; Committee Co-Chair: Rehg, James; Committee Member: Bobick, Aaron; Committee Member: Essa, Irfan; Committee Member: Smyth, Padhraic. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Srikanthan, Sasiharan Sudeshna. "An investigation of matrix switching topologies and algorithms." Thesis, University of Hertfordshire, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315633.
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Zimmerman, Eric Brady. "Analysis of the thermal behavior of telephone switching cabinets." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/17681.
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Babaali, Mohamed. "Switched Linear Systems: Observability and Observers." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-04122004-073020/unrestricted/babaali%5Fmohamed%5F200405%5Fphd.pdf.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004.Verriest, Erik, Committee Member ; Wardi, Yorai, Committee Member ; Yezzi, Anthony, Committee Member ; Wang, Yang, Committee Member ; Egerstedt, Magnus, Committee Chair. Vita. Includes bibliographical references (leaves 80-85).
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Rymut, Joseph E. "Development and Control of a Solar Array Switching Module." Cleveland State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=csu1198769150.
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Ragab, A. H. M. "A high capacity multiprocessor X.25 packet switching node." Thesis, University of Essex, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355389.
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Kim, Yoonkap. "Low temperature melting point metals for hot MEMS electrical switching." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/Y_Kim_121307.pdf.
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DeLong, Kenneth Wayne. "Two-photon absorption and color centers: Effects on all-optical switching." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185023.
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This dissertation explores the effects of two-photon absorption and color center induced absorption on all-optical switching devices. The amount of allowable two-photon absorption was quantified by the parameter T = 2βλ/n₂, where λ is the operating wavelength, β is the two-photon absorption coefficient, and n₂ is the nonlinear refractive index coefficient, the latter two being measured at λ. If the value of T exceeds unity, the operation of all-optical switching devices is in general degraded beyond usable regimes. This result was demonstrated by numerical experiments on systems of equations modelling a nonlinear directional coupler, a prototypical all-optical switching device. The value of T was measured in two fibers, one made of lead silicate glass, and one made of TiO₂-doped silica. We find the value of T to be greater than unity at a wavelength of 1.06 μm in both fibers. Significant color center formation was seen in the lead glass fiber. These color centers were created through two-photon absorption and destroyed through one-photon absorption. Color center induced absorption was seen to mimic two-photon absorption in certain regimes. The nonlinear optical response of semiconductor-doped glasses, an example of a one-photon resonant nonlinearity, was studied. A relaxation time which is dependent on the carrier density was found to be important when modelling the response of these glasses.
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Klugkist, Joost André. "Mechanisms for photonic switching in systems of strongly interacting dipoles." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/306046253.
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Ng, Kim Chwee. "Switching control systems and their design automation via genetic algorithms." Thesis, University of Glasgow, 1995. http://theses.gla.ac.uk/1556/.
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The objective of this work is to provide a simple and effective nonlinear controller. Our strategy involves switching the underlying strategies in order to maintain a robust control. If a disturbance moves the system outside the region of stability or the domain of attraction, it will be guided back onto the desired course by the application of a different control strategy. In the context of switching control, the common types of controller present in the literature are based either on fuzzy logic or sliding mode. Both of them are easy to implement and provide efficient control for non-linear systems, their actions being based on the observed input/output behaviour of the system. In the field of fuzzy logic control (FLC) using error feedback variables there are two main problems. The first is the poor transient response (jerking) encountered by the conventional 2-dimensional rule-base fuzzy PI controller. Secondly, conventional 3-D rule-base fuzzy PID control design is both computationally intensive and suffers from prolonged design times caused by a large dimensional rule-base. The size of the rule base will increase exponentially with the increase of the number of fuzzy sets used for each input decision variable. Hence, a reduced rule-base is needed for the 3-term fuzzy controller. In this thesis a direct implementation method is developed that allows the size of the rule-base to be reduced exponentially without losing the features of the PID structure. This direct implementation method, when applied to the reduced rule-base fuzzy PI controller, gives a good transient response with no jerking.
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Warde, Walid. "An investigation into alternatives for high performance ATM switching systems." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284964.
Full text
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Saitou, Kazuhiro. "Conformational switching in self-assembling mechnical systems : theory and application." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39774.
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Nielson, Gregory Nolan 1974. "Micro-opto-mechanical switching and tuning for integrated optical systems." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30332.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 243-260).
Integrated optical circuits have the potential to lower manufacturing and operating costs and enhance the functionality of optical systems in a manner similar to what has been achieved by integrating electronic circuits. One of the basic optical elements required to enable integrated optical circuits is an integrated optical switch, analogous to transistor switches used in integrated electronic circuits. An ideal switch for integrated optical circuits would provide wavelength-selective switching. Wavelength- selective behavior is an important characteristic for devices intended for networking applications as wavelength division multiplexing (WDM) of optical signals has become the accepted standard. A major contribution of this thesis is the design, fabrication, and experimental demonstration of a wavelength-selective, integrated optical switch. This switch operates by combining a microring resonator filter with a microelectromechanical system (MEMS) device that allows the normally static ring resonator filter to be switched on and off. This represents the first demonstration of a wavelength-selective integrated optical MEMS switch. Additional contributions of this work include a new study of dielectric charging, analysis of the use of titanium nitride as structural material for MEMS, two new MEMS actuation techniques that lead to higher speed and/or lower actuation volt- age, and a feasibility analysis for wavelength tuning using a generalized version of the switch design. A model for the evolution of dielectric charging during the actuation of MEMS devices was developed to address a deviation of the experimentally fabricated devices from the theoretical predictions according to older models.
(cont.) The new model predicts the experimental voltage versus displacement behavior of the wave-length selective switch accurately, and offers new insights into the physics of dielectric charging. The use of titanium nitride as a MEMS material was conceived as a solution to residual stress problems that are common in cantilever-type of actuators in general, including the wavelength-selective switch. Specific details on MEMS implementation using titanium nitride are discussed in the thesis. To address CMOS compatibility and speed challenges, two new complementary MEMS switch actuation techniques were developed. The new methods require less voltage and energy for actuation while at the same time reducing the switching time of the device to levels unachievable with current MEMS actuation techniques. Preliminary theoretical and experimental results are presented and discussed. Finally, the thesis covers the feasibility analysis of a version of the switch design where the motion is analog and, hence, can be used for tuning of resonant integrated optical structures. The analysis shows that the required positional accuracy is achievable with on-chip capacitive position sensing and feedback control, and points to a promising new direction for mechanically tunable integrated photonics. While these contributions are all outgrowths of work directed towards realizing an integrated optical circuit, they are also significant for applications such as radio- frequency (RF) MEMS switching and free-space optical MEMS devices (i.e. micro- mirror arrays for projection displays).
by Gregory Nolan Nielson.
Ph.D.
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Nimmagadda, Srinivas 1968. "Simultaneous switching noise and its impact on CMOS digital systems." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278252.
Full textAbstract:
Simultaneous switching noise was calculated for a number of CMOS drivers switching together. CMOS receiver noise immunity and the feed through of simultaneous switching noise from a D.C. "ON" driver were studied. The effects of skewing output driver switching on the simultaneous switching noise were explained. The performance trade-offs in using a damping resistor to minimize switching noise were analyzed. A distributed lumped equivalent model has been developed to model signal propagation over noisy reference planes, and thereby to accurately predict the overall noise levels in a system. The impact of package pin distribution on noise on the reference plane was analyzed.
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Ward, Ronald P. "Software Considerations in the Control of Digital Communications Switching Systems." International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/611926.
Full textAbstract:
International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, CaliforniaToday's complex implementations of integrated packet and circuit switched digital communications networks demand that the software used for controlling these systems be robust, fault tolerant, and capable of runtime recovery from all but the most severe of operational errors. The typical modern switched communications system includes the use of multiple circuit switches, each with potentially thousands of end-user interfaces. Further, these switches are often inter-connected to each other via high-capacity trunks. A single connection between two end-user interfaces often traverses a number of intermediate circuit switches in order to effect the end-to-end communications desired. In this complex, distributed environment, the establishment and dissolution of end-to-end user connections involve far more than simple binary connection states indicating the existence, or non-existence, of a link. More commonly, a single end-to-end connection requires multiple node links across multiple, heterogeneous interfaces. The command and control software used to establish, monitor, and dissolve these connections must be capable of dealing with errors which arise at any node along the way in a consistent and reliable manner. Most critically, the system software must be capable of maintaining an accurate, multi-level mapping of distributed resources' availability, allocation, and status. Further, the software must have the capability of "healing itself" during operational run-time when it can, and of accurately reporting the nature of inconsistencies caused by anomalous events that cannot be fixed on the fly. The Edwards Digital Switch (EDS), developed by CSTI, provides a case study of possible solutions, and potential pitfalls, that can arise in the design, development, and implementation of the controlling software in today's dynamic, distributed communications' system architectures.
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Patrick, Hugh Alton Jr. "An Empirical Evaluation of Human Figure Tracking Using Switching Linear Models." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4838.
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One of the difficulties of human figure tracking is that humans move their bodies in complex, non-linear ways. An effective computational model of human motion could therefore be of great benefit in figure tracking. We are interested in the use of a class of dynamic models called switching linear dynamic systems for figure tracking.
This thesis makes two contributions. First, we present an empirical analysis of some of the technical issues involved with applying linear dynamic systems to figure tracking. The lack of high-level theory in this area makes this type of empirical study valuable and necessary. We show that sensitivity of these models to perturbations in input is a central issue in their application to figure tracking. We also compare different types of LDS models and identification algorithms.
Second, we describe 2-DAFT, a flexible software framework we have created for figure tracking. 2-DAFT encapsulates data and code involved in different parts of the tracking problem in a number of modules. This architecture leads to flexibility and makes it easy to implement new tracking algorithms.
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Akcay, Didem. "Inference Of Switching Networks By Using A Piecewise Linear Formulation." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606901/index.pdf.
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Inference of regulatory networks has received attention of researchers from many fields. The challenge offered by this problem is its being a typical modeling problem under insufficient information about the process. Hence, we need to derive the apriori unavailable information from the empirical observations. Modeling by inference consists of selecting or defining the most appropriate model structure and inferring the parameters. An appropriate model structure should have the following properties. The model parameters should be inferable. Given the observation and the model class, all parameters used in the model should have a unique solution restriction of the solution space). The forward model should be accurately computable (restriction of the solution space). The model should be capable of exhibiting the essential qualitative features of the system (limit of the restriction). The model should be relevant with the process (limit of the restriction). A piecewise linear formulation, described by a switching state transition matrix and a switching state transition vector with a Boolean function indicating the switching conditions is proposed for the inference of gene regulatory networks. This thesis mainly concerns using a formulation of switching networks obeying all the above mentioned requirements and developing an inference algorithm for estimating the parameters of the formulation. The methodologies used or developed during this study are applicable to various fields of science and engineering.
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Cha, Sung Han. "Guaranteed safe switching for switching adaptive control." Phd thesis, 2010. http://hdl.handle.net/1885/150267.
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Adaptive control algorithms may not behave well in practice due to discrepancies between the theory and actual practice. The proposed results in this manuscript constitute an effort in providing algorithms which assure more reliable operation in practice. Our emphasis is on algorithms that will be safe in the sense of not permitting destabilizing controllers to be switched in the closed-loop and to prevent wild signal fluctuations to occur. Coping with the connection or possible connection of destabilizing controllers is indeed a daunting task. One of the most intuitive forms of adaptive control, gain scheduling, is an approach to control of non-linear systems which utilizes a family of linear controllers, each of which provides satisfactory control for a different operating point of the system. We provide a mechanism for guaranteeing closed-loop stability over rapid switching between controllers. Our proposed design provides a simplification using only finite number of pre-determined values for the controller gain, where the observer gain is computed via a table look-up method. In comparison to the original gain scheduling design which our procedure builds on, our design achieves similar performance but with much less computational burden. Many multi-controller adaptive switching algorithms do not explicitly rule out the possibility of switching a destabilizing controller into the closed-loop. Even if the new controller is ensured to be stabilizing, performance verification with the new controller is not straightforward. The importance of this arises in iterative identification and control algorithms and multiple model adaptive control (MMAC). We utilize a limited amount of experimental and possibly noisy data obtained from a closed-loop consisting of an existing known stabilizing controller connected to an unknown plant-to infer if the introduction of a prospective controller will stabilize the unknown plant. We propose analysis results in a nonlinear setting and provide data-based tests for verifying the closed-loop stability with the introduction of a new nonlinear controller to replace a linear controller. We also propose verification tools for the closed-loop performance with the introduction of a new stabilizing controller using a limited amount of data obtained from the existing stable closed-loop. The simulation results in different practical scenarios demonstrate efficacy and versatility of our results, and illustrate practicality of our novel data-based tests in addressing an instability problem in adaptive control algorithms.
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"Architectures of new switching systems." 1998. http://library.cuhk.edu.hk/record=b5889524.
Full textAbstract:
by Lam Wan.Thesis submitted in: November 1997.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references (leaves 96-102).
Abstract also in Chinese.
Part I
Chapter 1 --- Introduction to Integrated Intelligent Personal Communication System --- p.1
Chapter 2 --- The Switching Architecture --- p.5
Chapter 2.1 --- The Overall Switching Architecture --- p.6
Chapter 2.2 --- Switching Module --- p.10
Chapter 2.2.1 --- Traffic Routing in Switching Module --- p.11
Chapter 2.2.2 --- Structure of Switching Module --- p.15
Chapter 2.2.3 --- Wireless Base Interface --- p.16
Chapter 2.2.4 --- Trunk Interface --- p.18
Chapter 2.2.5 --- Analog Interfaces --- p.18
Chapter 2.3 --- Network Intelligence --- p.19
Chapter 2.4 --- Wireless Part --- p.21
Chapter 2.4.1 --- Call-Setup in IIPCS --- p.24
Chapter 2.4.2 --- Handoff --- p.25
Chapter 2.4.3 --- Wireless Base --- p.27
Chapter 2.5 --- Downstream Wired Extensions --- p.28
Chapter 2.6 --- Upstream Wired Part --- p.28
Chapter 2.7 --- Voice System --- p.28
Chapter 2.8 --- Features of the IIPCS --- p.29
Chapter 3 --- Concluding Remarks --- p.33
Chapter 3.1 --- Summary --- p.35
Chapter 3.2 --- Directions for Further Research --- p.36
Part II
Chapter 4 --- Introduction to Next-Generation Switch --- p.37
Chapter 5 --- Architecture of Next-Generation Switch --- p.41
Chapter 5.1 --- Overall Architecture of Next-Generation Switch --- p.42
Chapter 5.1.1 --- Interface module --- p.44
Chapter 5.1.2 --- Packetizer --- p.46
Chapter 5.2 --- Concentration Fabric --- p.50
Chapter 5.3 --- Shared-Buffer Memory Switch --- p.53
Chapter 6 --- Concentration Networks --- p.56
Chapter 6.1 --- Background of Concentration Networks --- p.56
Chapter 6.2 --- k-Sorting --- p.63
Chapter 6.3 --- Concentrator --- p.72
Chapter 6.3.1 --- Nk-to-k Concentrator --- p.73
Chapter 6.3.2 --- Match between Circles with Cost Reduction --- p.75
Chapter 6.4 --- The Structure of a Molecule --- p.78
Chapter 6.5 --- Summary --- p.81
Chapter 7 --- Lock-Latch Algorithm --- p.82
Chapter 8 --- Performance Evaluation --- p.88
Chapter 9 --- Concluding Remarks --- p.93
Chapter 9.1 --- LSI Implementation --- p.94
Chapter 9.2 --- Summary --- p.95
Bibliography
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Tousi, Mani Mesgarpour. "Supervisory control of switching control systems." Thesis, 2006. http://spectrum.library.concordia.ca/8888/1/MR14271.pdf.
Full textAbstract:
In this thesis, we show that the problem of designing a switching policy for an adaptive switching control system can be formulated as a problem of Supervisory Control of a Discrete-Event System (DES). Two important problems in switching control are then addressed using the DES formulation and the theory of supervisory control under partial observation. First we examine whether for a given set of controllers, a switching policy satisfying a given set of constraints (on the transitions among controllers) exists. If so, then we design a minimally restrictive switching policy. Next, we introduce an iterative algorithm for finding a minimal set of controllers for which a switching policy satisfying the switching constraints exists. In our study we show that in the supervisory control problem considered in this thesis, limitation on event observation is the factor that essentially restricts supervisory control. In other words, once observation limitations are respected, limitation on control will be automatically satisfied. We use the above result to simplify our iterative algorithm for finding minimal controller set.
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WU, ZHAO-XIANG, and 吳兆祥. "Feeder switching strategies of distribution systems." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/87851800204292006680.
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"Resistive switching in silicon oxide-based systems." Thesis, 2010. http://hdl.handle.net/1911/62109.
Full textAbstract:
Voltage-controlled resistive switching in various gap systems on SiO2 substrates is demonstrated. The nanosized gaps are made by several means using different materials including metals, semiconductors and amorphous carbon. The switching site is further reduced in size by using multi-walled carbon nanotubes and single-walled carbon nanotubes. The switching in all the gap systems shares the same characteristics. This independence of switching on the material compositions of the electrodes, accompanied by observable damage to the SiO2 substrate at the gap region, bespeaks the intrinsic switching from post-breakdown SiO2. It calls for caution when studying resistive switching in nanosystems on oxide substrates, since oxide breakdown extrinsic to the nanosystem can mimic resistive switching. Meanwhile, the devices show promising memory properties. The observed intermediate states reveal the filamentary nature of the switching. The switching is further explored in a vertical representation as potential candidate for high-density memory applications.
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Jin, Xing. "Multiple ARX Model Based Identification for Switching/Nonlinear Systems with EM Algorithm." Master's thesis, 2010. http://hdl.handle.net/10048/1056.
Full textAbstract:
Two different types of switching mechanism are considered in this thesis; one is featured with abrupt/sudden switching while the other one shows gradual changing behavior in its dynamics. It is shown that, through the comparison of the identification results from the proposed method and a benchmark method, the proposed robust identification method can achieve better performance when dealing with the data set mixed with outliers.
To model the switched systems exhibiting gradual or smooth transition among different local models, in addition to estimating the local sub-systems parameters, a smooth validity (an exponential function) function is introduced to combine all the local models so that throughout the working range of the gradual switched system, the dynamics of the nonlinear process can be appropriately approximated. Verification results on a simulated numerical example and CSTR process confirm the effectiveness of the proposed Linear Parameter Varying (LPV) identification algorithm.Process Control