Dissertations / Theses on the topic 'Multi-mode'
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Arita, Yoshihiko. "Multi-mode absorption spectroscopy." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489407.
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A novel approach to absorption spectroscopy is presented which achieves, simultaneously, wide spectral coverage and high spectral resolution. The principle of the technique - dubbed multi-mode absorption spectroscopy (MUMAS) - is described, and demonstrations of the principle are reported using two multi-mode sources: diode lasers and micro-cavity solid state lasers. The technique is shown to have potential for the detection of multiple species and multiple parameters using a single laser and a single detector.
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Yin, Hang. "Mode switch for component-based multi-mode systems." Licentiate thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-16153.
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Component-based software engineering is becoming a prominent solution to the development of complex embedded systems. Since it allows a system to be built by reusable and independently developed components, component-based development substantially facilitates the development of a complex embedded system and allows its complexity to be better managed. Meanwhile, partitioning system behavior into multiple operational modes is also an effective approach to reducing system complexity. Combining the component-based approach with the multi-mode approach, we get a component-based multi-mode system, for which a key issue is its mode switch handling. The mode switch of such a system corresponds to the joint mode switches of many hierarchically organized components. Such a mode switch is not trivial as it amounts to coordinate the mode switches of different components that are independently developed. Since most existing approaches to mode switch handling assume that mode switch is a global event of the entire system, they cannot be easily applied to component-based multi-mode systems where both the mode switch of the system and each individual component must be considered, and where components cannot be assumed to have global knowledge of the system. In this thesis, we present a mechanism---the Mode Switch Logic (MSL)---which provides an effective solution to mode switch in component-based multi-mode systems. MSL enables a multi-mode system to be developed in a component-based manner, including (1) a mode-aware component model proposed to suit the multi-mode context; (2) a mode mapping mechanism for the seamless composition of multi-mode components and their mode switch guidance; (3) a mode switch runtime mechanism which coordinates the mode switches of all related components so that the mode switch can be correctly and efficiently performed at the system level; and (4) a timing analysis for mode switches realized by MSL. All the essential elements of MSL are additionally demonstrated by a case study.ARROWS
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Sharabati, Walid. "Multi-mode and evolutionary networks." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3384.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 214-215. Thesis director: Edward J. Wegman, Yasmin H. Said Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Title from PDF t.p. (viewed Mar. 9, 2009). Includes bibliographical references (p. 209-213). Also issued in print.
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Mousa, M. A. "Optimisation in multi-mode systems." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3022557/.
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We study cost optimisation in multi-mode systems with discrete costs. We first solve the problem in one dimension and next we study it in multiple dimensions. As a motivating example, we study the temperature control in buildings using heating, ventilation and air-conditioning system HVAC while paying the minimal cost as possible. By optimising the behaviour of the HVAC systems, lots of energy could be saved. We are interested in finding optimal solutions as well as approximate solutions with guarantees.
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Luhaib, Saad Wasmi Osman. "Multi-mode dielectric resonator filters." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20843/.
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Dielectric resonator (DR) filters are widely used in microwave communications due to their small size and high Q-factor. Multi-mode filters offer a further level of miniaturisation. A new multi-mode dielectric resonator filter is presented in this thesis. The TE11d dual-mode DR offers an 11% size reduction ratio compared with a coaxial air-filled filter with the same unloaded Q-factor (Qu) and about 820 MHz spurious separation from the fundamental frequency 1.95 GHz. Two coupling techniques are applied in the TE11d filter configuration. These are: ceramic puck/probe in contact and etching holes through the ceramic puck for probe installation. A 4th order Chebyshev filter dual-mode DR filter has been simulated and fabricated using each technique. The results show a good agreement between the simulation and measurement with half spurious-free window compared with non-loaded cavity. In the etching method, the spurious-free window and the Qu improved compared with unpatterned ceramic puck. The inline structure filter provides an extra improvement in the spurious window base for the planar configuration. Another approach to the dual-mode DR filter has been studied in this work. A HE11 dual-mode with ceramic puck placed at the base of the cavity presents a good size reduction ratio and acceptable spurious window. The mathematical model shows that transmission zeros (TZs) can be generated in all orientation cases of the inter-resonator coupling hole. The control range of the TZs positions was from 40 MHz from the centre frequency. A good agreement was obtained between the simulation and the measurement results. A triple-mode DR filter with two-piece of the ceramic puck in parallel has been presented. The one cavity approach offers a high Q-factor with 400 MHz suppression. A coaxial probe was used for the input/output coupling and the etching hole through the ceramic puck for inter-resonator coupling. A 3rd order Chebyshev DR filter was simulated and fabricated with two TZs on the upper sideband. The practical results show prospects in application of the filter for miniaturised microwave communications.
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O'Hagan, Seamus. "Multi-mode absorption spectroscopy for multi-species and multi-parameter sensing." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:6f422683-7c50-47dd-8824-56b4b4ea941d.
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The extension of Multi-mode Absorption Spectroscopy (MUMAS) to the infra-red spectral region for multi-species gas sensing is reported. A computationally efficient, theoretical model for analysis of MUMAS spectra is presented that avoids approximations used in previous work and treats arbitrary and time-dependent spectral intensity envelopes, thus facilitating the use of commercially available Interband Cascade Lasers (ICLs) and Quantum Cascade Lasers (QCLs). The first use of an ICL for MUMAS is reported using a multi-mode device operating at 3.7 μm to detect CH4 transitions over a range of 30 nm. Mode-linewidths are measured using the pressure-dependent widths of an isolated absorption feature in HCl. Multi- species sensing is demonstrated by measurement of partial pressures of CH4, C2H2 and H2CO in a low-pressure mixture with uncertainties of around 10%. Detection of CH4 in N2 at 1 bar is demonstrated using a shorter-cavity ICL to resolve spectral features in pressure-broadened and congested spectra. The first use of a QCL for MUMAS is reported using a commercially available device operating at 5.3 μm to detect multiple absorption transitions of NO at a partial pressure of 2.79 μbar in N2 buffer gas. The revised model is shown to enable good fits to MUMAS data by accounting for the time-variation of the spectral intensity profile during frequency scanning. Individual mode-linewidths are derived from fits to pressure- dependent MUMAS spectra and features from background interferences due to H2O in laboratory air are distinguished from those of the target species, NO. Data obtained at scan rates up to 10 kHz demonstrate the potential for achieving short measurement times. The development of a balanced ratiometric detection scheme for MUMAS with commercially available multi-mode lasers operating at 1.5 μm is reported for simultaneous detection of CO and CO2 showing improved SNR performance over previous direct transmission methods and suitability for a compact field-employable instrument. In addition, MUMAS spectra of CO2 are used to derive gas temperatures with an uncertainty of 3.2% in the range 300 - 700 K.
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Northern, Jonathen Henry. "Multi-species detection using Infrared Multi-mode Absorption Spectroscopy." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:10f3bd62-4c81-4eaf-854d-1f388af73be9.
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This thesis reports work extending the scope of a recently developed gas sensing technique, multi-mode absorption spectroscopy (MUMAS). The ability of MUMAS to simultaneously detect multiple species from a mixture is demonstrated for the first time. The technique is subsequently extended to mid-infrared wavelengths, realising large gains in sensitivity. A solid-state, multi-mode laser has been developed to provide a high-performance comb source for use with MUMAS. This in-house constructed, diode-pumped, Er/Yb:glass laser operates on 10 longitudinal modes, separated by 18 GHz and centred close to 1565 nm. The extensive development and prototyping work leading to this final laser design is described. Multi-species detection with MUMAS is reported for the first time, thus demonstrating the ability of this technique to perform multi-gas sensing using a single laser and simple detection scheme. The previously described Er/Yb multi-mode laser was used to record MUMAS signals from a sample containing CO, C2H2, and N2O. The components of the mixture were detected simultaneously by identifying multiple transitions in each of the species. Temperature- and pressure-dependent modelled spectral fits to the data were used to determine the partial pressures of each species in the mixture with an uncertainty better than +/-2%. Multi-mode radiation has been successfully generated at 3.3 μm using quasi phase matched difference frequency generation (QPM-DFG). A mid-infrared laser comb was produced by optically mixing the near-infrared, multi-mode comb produced by the previously developed Er/Yb:glass laser with the single-mode output of a Nd:YAG laser operating at 1064 nm. This multi-frequency laser source was characterised to verify performance, and subsequently used to perform proof-of-principle MUMAS measurements on the strong transitions found in this spectral region. Spectra were recorded of NH3 and CH4 both individually and as components of a mixture. A minimum detection level for this system was determined to be 4.3 μbar m-1 for CH4, a sensitivity increase of 300 over similar measurements performed in the near-IR.
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Chu, Diyang. "Design Validation of Multi-mode Systems." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311576.
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Cyber-Physical Systems(CPS) are a group of systems that are involved with both physical processes and computational processes. The interaction of physical components and computational components makes it difficult to analyze, design and verify this type of systems. The problem becomes more complex when certain input or decision of these systems must be initiated by human. Cyber-Physical Systems with human operator in the loop are called Embedded Human Systems(EHS). To ensure the safety of EHS such as traffic control systems, space shuttle control systems, nuclear power plant control systems and so on, it is critically important for human operators to fully understand both physical and computational processes. However, humans are usually easily overwhelmed by concurrent information, the situation becomes worse when it comes to complex EHS with timing constraints.This dissertation proposes a domain specific modeling language that takes advantage of hybrid system abstraction to retain important system behaviors and automatically generates self-configured system verification software. The verification software could effectively reduce the computation time with parallel scheduling algorithm, thus the computation process that violates the design protocol can be halted without wasting computation resources. The modeling environment also allows user to conveniently set design constraints to avoid flaws early in prototype phase and reuse the available model for a family of different platforms. Several verification results of different platforms are shown to demonstrate the efficiency and reusability of the modeling environment.
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Abdi, Moussa. "Détection multi-utilisateurs en mode CDMA /." Paris : École nationale supérieure des télécommunications, 2003. http://catalogue.bnf.fr/ark:/12148/cb390325301.
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Dure, Daniel. "Simulation multi-mode de circuits VLSI." Paris 11, 1989. http://www.theses.fr/1989PA112025.
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Alors que la conception des circuits intégrés de haute densité a été grandement facilité par toute une nouvelle génération d'outils d'aide à la synthèse, la simulation demeure un goulot d'étranglement pour ce processus. Nous revoyons ici un ensemble d'améliorations possibles des techniques de simulation récentes. Nous plaidons également en faveur d'une meilleure intégration de la simulation dans le système de conception. Un certain nombre de méthodes sont envisagées à cette fin. Plus précisément, une étude systématique des divers usages de la simulation met en valeur les problèmes susceptibles d'être rencontrés durant la simulation mais également durant les échanges de données entre applications. Cela conduit à une nouvelle organisation du système de conception, aidée par un protocole de communication piloté par des évènements clairement identifiés. Le noyau d'un simulateur à évènements discrets est détaillé, ainsi qu'un modèle général pour la simulation logique, qui permet une vitesse de simulation de 50000 évènements par seconde et par MIPS, sur machine séquentielle. Cette échelle de performance a été rendue possible par l'usage de nouvelles structures de données et par la curyfication des fonctions d'évaluation des modèles de composants. Notre méthode fait également appel à un modèle continue de la charge d'une capacité, permettant une meilleure prise en compte des parasites que les modèles "une passe" classiques. D'autres méthodes taillées pour la simulation de composants de plus bas et de plus hauts niveaux sont aussi présentées. Les problèmes pratiques rencontrés durant le développement des simulateurs multi-mode sont évoqués et pris en compte par une méthodologie orientée objet, basée sur un nouvel environnement de programmation et de simulationWhereas design of VLSI circuits has been sped up by a new crop of synthetisis tools, simulation still constitutes a bottleneck in this process. In this paper, we review existing simulation methods and some improvements of our own. We also advocate for better integration of simulation within the design system, and we present new techniques to this end. To be more precise, a systematic study of simulation usages highlights potential problems during simulation and data exchange. This leads to a new organization of the design system, supported by an event driven communication protocol. The kernel of an event driven simulator is detailed, along with a general purpose model for logic simulation, which enables simulation speed of 50000 events per second per MIPS, on sequential computers. This level of performance has been reached through the usage of new simulatable data structures and currying of device evaluation functions. This method also uses a continuous charge delay model, which handles spikes more accurately than classical one pass delay models. Other methods tailored for the simulation of higher and lower level devices are also presented, and practical problems encountered during development of multi-mode simulators are listed and addressed through an object oriented methodology supported by a new simulation and software environment
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Abdi, Moussa. "Détection multi-utilisateurs en mode CDMA." Paris, ENST, 2002. http://www.theses.fr/2002ENST0027.
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Robar, Brian. "An FM receiver architecture for dual-mode/multi-mode mobile receivers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ57736.pdf.
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Islam, S. "Multi-way mode-interference and warped-mode microwave combline directional couplers." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383171.
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Robar, Brian (Brian David) Carleton University Dissertation Engineering Electronics. "An FM receiver architecture for dual-mode/multi-mode mobile receivers." Ottawa, 2000.
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Legg, Stephen. "Multi-mode receiver systems for cosmic microwave background B-mode polarisation experiments." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/multimode-receiver-systems-for-cosmic-microwave-background-bmode-polarisation-experiments(11399beb-9f3d-455b-b236-7d612ab1a00b).html.
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A measurement of the primordial B-mode polarisation of the Cosmic Microwave Background would provide direct evidence of inflation in the early universe. The extremely weak nature of the B-mode signal necessitates an instrument with a high sensitivity and precise control over systematic effects. Multi-mode antenna feed horns offer higher sensitivity than their single-mode counterparts, however their behaviour is much more complex. The Short Wavelength Instrument for the Polarisation Explorer (SWIPE) onboard the Large Scale Polarisation Explorer (LSPE) is one instrument planning to implement multi-mode feed horns. SWIPE will attempt to detect the primordial B-mode at large angular scales, measuring the sky in three bands at 140, 220 and 240 GHz. A single on-axis High-Density PolyEthylene (HDPE) lens and polarisation-splitting wire grid combine to focus the radiation from the sky onto two focal planes of multi-mode horns feeding bolometric detectors. A large diameter rotating metal-mesh half-wave plate allows both polarisations to be measured by the same pixel, therefore bypassing many detector systematics. Simulations are performed to predict the sky beam for two key pixels: closest to and furthest from the centre of the focal plane. For the 140 GHz channel the cross-polarisation is predicted, and the optimum location at which to place the telescopeâs focus behind the horn aperture to maximise gain and optimise beam shape is investigated. A measurement of the multi-mode horn is performed using a room-temperature bolometer. An investigation is also conducted to assess to what extent the same measurements can be performed using a coherent measurement system such as a vector network analyser. A working coherent measurement technique is devised, however it is limited to horns carrying only the first 3 modes.
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Dujardin, Yann. "Régulation adaptative multi-objectif et multi-mode aux carrefours à feux." Phd thesis, Université Paris Dauphine - Paris IX, 2013. http://tel.archives-ouvertes.fr/tel-00904781.
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Afin de répondre à la problématique de la régulation multi-objectif et multi-mode des carrefours à feux, nous proposons trois modèles de programmation linéaire mixte en nombres entiers constituant les moteurs d'un système de régulation pleinement adaptatif, ainsi que deux procédures interactives d'optimisation multi-objectif permettant d'adapter itérativement une "politique de régulation" à la situation de trafic. Les critères pris en compte, tous à minimiser, sont le temps d'attente et le nombre d'arrêts des véhicules particuliers, et un critère dédié aux transports en commun permettant de fixer un temps d'attente souhaité pour chaque bus. Des expérimentations ont montré qu'un des trois modèles, dit hybride, se démarque positivement des deux autres. Ce modèle a alors été mis en œuvre avec une des deux procédures interactives, permettant de contrôler un trafic simulé sur une période d'une heure dans différents scénarios types, et comparé à un système de régulation semi-adaptatif.
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Thomas, Willie L. II, Samuel Berhanu, and Nathan Richardson. "System Framework for a Multi-Band, Multi-Mode Software Defined Radio." International Foundation for Telemetering, 2014. http://hdl.handle.net/10150/577442.
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ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CAThis paper describes a system framework for a multi-band, multi-mode software defined radio (MBMM SDR) being developed for next-generation telemetry applications. The system framework consists of the multi-band front-end (MBFE), the multi-mode digital radio (MMDR), and the configuration and control (C2) sub-systems. The MBFE consists of an L/S/C-band transceiver architecture that provides wideband operation, band selection, and channel tuning. The MMDR consists of the software and firmware components for high-speed digital signal processing for the telemetry waveforms. Finally, the C2 consists of the software and hardware components for system configuration, control and status. The MBFE is implemented as a standalone hardware sub-system, while the MMDR and C2 are integrated into a single hardware subsystem that utilizes state-of-the-art system-on-chip (SoC) technology. Design methodologies, hardware architectures, and system tradeoffs are highlighted to meet next-generation telemetry requirements for improved spectrum efficiency and utilizations. Approved for public release; distribution is unlimited (412TW-PA-14281).
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Guitton, Gabrielle. "Design methodologies for multi-mode and multi-standard low-noise amplifiers." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0861/document.
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L'engouement récent pour l'Internet des Objets comme pour les communications satellites entraine des besoins forts en systèmes de communication radio-fréquence (RF) performants. Afin de répondre aux contraintes du marché de masse, ces systèmes doivent être toujours moins encombrants et permettre de maitriser leur consommation de puissance. Ils doivent également être capable d'adresser plusieurs standards de communications et d'ajuster leur performances aux besoins de leur environnement, toujours afin de réduire leur taille et leur consommation. Actuellement, beaucoup de travaux se concentrent sur le développement d'amplificateurs faible-bruits (LNA), le bloc le plus critique des récepteurs RF. L'objectif est donc de concevoir des récepteurs multi-mode et multi-standard. Pour cela, les LNA nécessitent des flots de conception capables de s'adapter aux différentes technologies et topologies afin de répondre à des cahiers des charges très diverses. Cette thèse a donc pour objectif le développement de méthodologies de conception simple et précise pour l'implémentation d'amplificateurs faible bruit.La première méthodologie présentée est dédiée à l'implémentation de LNA en technologie COTS pour des applications spatiales. Ce LNA présente une adaptation large-bande pour adresser plusieurs standards. Il a été conçu pour faire partie d'un récepteur RF dédié aux nano-satellites. Ce dernier a donc fait l'objet d'une étude préliminaire afin de déterminer le cahier des charges à partir des normes des standards visés.La seconde méthodologie est dédiée à l'implémentation de LNA en technologie CMOS pour n'importe quelle type d'applications. Cette méthodologie est d'abord présentée au travers de topologies simples, puis appliquée à un LNA sans inductances à forte linéarité. Cette méthodologie permet notamment de comparer les topologies mais également les technologies CMOS, même les plus avancées telle que la 28 nm FDSOI.Enfin le LNA sans inductances est rendu reconfigurable pour adresser plusieurs standards tout en gardant le dimensionnement optimum obtenu par la méthodologie présentée précédemment. En effet les tailles et polarisation de chaque transistor sont contrôlées numériquement afin d'adapter les performances du LNA à un standard donné. De plus, l'étude de filtres de type N-path combinés au LNA proposé permet d'étendre encore la linéarité du circuitThe recent enthusiasm for the Internet of Objects as well as for satellite communications leads to the need for high-performance radio-frequency (RF) communication systems. In order to meet the constraints of the mass market, these systems must be compact and be as low power as possible. Beside, they are expected to address multiple communication standards and to adjust their performance to the environment, still in order to reduce the size and the power consumption. Currently, many works focus on the development of low-noise amplifiers (LNA), the most critical block of RF receivers. To address this purpose, the goal is to design multi-mode and multi-standard receivers. Hence, LNAs require design flows that can adapt to the different technologies and topologies in order to meet any given set of specifications. This thesis aims at the development of simple and accurate design methodologies for the implementation of low-noise amplifiers.The first proposed methodology is dedicated to the implementation of a LNA in COTS technology for spatial applications. This LNA offers a broadband matching to address several standards. It is designed to be part of an RF receiver for nano-satellites. Thus, the latter is first studied in order to determine the specifications based on the standards of the targeted applications.The second methodology is dedicated to the implementation of LNAs in CMOS technology for any kind of applications. This methodology is first illustrated with basic topologies and then applied to an highly linear inductorless LNA. The design methodology also enables a fair comparison between the topologies and also CMOS technologies, even the most advanced ones such as the 28 nm FDSOI.Finally, reconfigurability is added to the inductorless LNA, to address several standards while retaining the optimum sizing given by the previously introduced methodology. Indeed, the size and polarization of each transistor are digitally controlled in order to adjust the LNA's performance to a given standard. Furthermore, the study of N-path filters combined with the proposed LNA is explored to improve the linearity of the circuit
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Ahmed, Walid K. M., and Harald Wougk. "DESIGN AND PERFORMANCE OF A MULTI-MODE MULTI-RATE TELEMETRY TRANSMITTER." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604584.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaTypical telemetry transmitter designs have focused on analog-circuit implementations, which suffer limitations when required to support multi-mode and multi-rate capabilities. In this paper, we introduce a transmitter design (and associated techniques) that employ an all-digital baseband line-up that utilizes only one single-rate clock. Thus, keeping the analog hardware to a minimum and providing the maximum possible flexibility through digital programmability, in order to efficiently support multi-mode (i.e., various modulation schemes) and multi-rate (i.e., various bit-rates) capabilities. The telemetry standard is defined in the IRIG 106-04 specification document published by the Range Commanders Council (RCC) government telemetry group [1]. The Telemetry standard supports several modulation schemes all of which fall under the general modulation family of continuous phase modulation (CPM). Out of such a family of modulation schemes, the work presented in this paper focuses on two modulation schemes as examples, namely, SOQPSK and the PCM/FM. However, this does not limit the scope of the ideas and techniques proposed in this paper. We present various design techniques as well as implementation considerations. We also present actual measured results using a test-bed and a synthesizer IC that have been developed in our laboratories. Finally, we compare the measured results with simulations in order to validate the performance of our implemented design.
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Pan, Hongqi 1961. "Fuzzy multi-mode resource-constrained project scheduling." Monash University, School of Business Systems, 2003. http://arrow.monash.edu.au/hdl/1959.1/5735.
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Hugo, Etienne Martin. "Automated design of multi-mode fuzzy controllers." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51631.
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Dissertation (PhD)--University of Stellenbosch, 2000.ENGLISH ABSTRACT: A standard fuzzy logic controller is not robust enough to guarantee consistent closed-loop performance for highly non-linear plants. A finely tuned closed-loop response loses relevance as the system dynamics change with operating conditions. The self-adaptive fuzzy logic controller can track changes in the system parameters and modify the controller parameters accordingly. In most cases, self-adaptive fuzzy logic controllers are complex and rely on some form of mathematical plant model. The multi-mode fuzzy logic controller extends the working range of a standard fuzzy logic controller by incorporating knowledge of the non-linear system dynamics into the control rule-base. The complexity of the controller and difficulty in finding control rules have limited the application of multi-mode fuzzy logic controllers. An automated design algorithm is proposed for the design of a multi-mode control rule-base using qualitative plant knowledge. The design algorithm is cost function-based. The closed-loop response, local to a domain of the non-linear state space, can be tuned by manipulation of the cost function weights. Global closed-loop response tuning can be done by manipulation of the controller input gains. Alternatively, a self-learning or self-adaptive algorithm can be used in a model reference adaptive control architecture to optimise the control rule-base. Control rules responsible for unacceptable closed-loop performance are identified and their consequences modified. The validity of the proposed design method is evaluated in five case studies. The case studies illustrate the advantages of the multi-mode fuzzy logic controller. The results indicate that the proposed self-adaptive algorithm can be used to optimise a rule-base given a required closed-loop specification. If the system does not conform to the model reference adaptive architecture then the intuitive nature of the cost function based design algorithm proves to be an effective method for rule-base tuning.
AFRIKAANSE OPSOMMING: Standaard wasige logika beheerders is nie noodwendig robuust genoeg om goeie geslote lus werkverrigting vir hoogs nie-liniere aanlegte te waarborg nie. In Perfek ge-optimeerde beheerder se geslote lus werkverrigting mag verswak indien die aanleg-parameters weens bedryfstoestande verander. Self-aanpassende beheerders kan die verandering in die aanleg-parameters volg en die beheerder dienooreenkomstig optimeer. As In reël is In self-aanpassende beheerder kompleks en afhanklik van In wiskundige model van die aanleg. Die multi-modus wasige logika beheerder vergroot die werksbereik van die standaard wasige logika beheerder deur kennis aangaande die stelsel se bedryfstoestand en stelselparameters in die reël-basis in te bou. Die aanwending van die multi-modus beheerder word tans beperk deur die struktuur kompleksiteit en moeilike optimering van die reël-basis. In Ge-outomatiseerde multi-modus reël-basis ontwerps-algoritme wat gebruik maak van kwalitatiewe kennis van die aanleg en In kostefunksie word in hierdie proefskrif voorgestel. Die geslote lus gedrag beperk tot In gebied in die toestands-ruimte kan ge-optimeer word deur die kostefunksie gewigte te manipuleer. Die globale werkverrigting kan ge-optimeer word met die beheerder intree aanwinste. In Self-aanpassende algoritme in In model-verwysings aanpassende argitektuur word as altematieftot reël-basis optimering voorgestel. Reëls verantwoordelik vir swak werkverrigting word ge-identifiseer en verbeter deur modifikasie van die reëls se gevolgtrekkings. Die voorgestelde ontwerps-metode word deur middel van vyf gevallestudies ondersoek. Die studies dui die voordele van die multi-modus struktuur aan. Die self-aanpassende argitektuur is In kragtige hulpbron om In reël-basis te optimeer vir In gegewe geslote lus spesifikasie. Hierdie proefskrif toon aan dat indien die stelsel nie aan die vereistes van In model verwysingstelsel voldoen nie, is die kostefunksie benadering tot reël-basis ontwerp In aantreklike en intuïtief verstaanbare opsie om die reël-basis te optimeer.
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Yu, Xi. "Multi-mode low temperature scanning probe microscopy." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404031.
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Naeem, Khawar. "Tolerance Analysis of a Multi-mode Ceramic Resonator." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-15577.
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Darlison, A. G. "Multi-mode effects in Jahn-Teller absorption spectra." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370246.
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Guo, Jing. "MULTI-MODE SELF-REFERENCING SURFACE PLASMON RESONANCE SENSORS." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/13.
Full textAbstract:
Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation between surface and bulk effects. By using an angular interrogation, both surface plasmons are simultaneously excited at the same location and wavelength but at different angles. Angular interrogation offers at least a factor of 3.6 improvement in surface and bulk cross-sensitivity compared to wavelength-interrogated dual-mode SPR sensors.
Multi-mode SPR sensors supporting at least three surface-plasmon modes can differentiate a target surface effect from interfering surface effects and bulk index changes. This dissertation describes a tri-mode SPR sensor which supports three surface plasmon resonance modes at one single sensing position, where each mode is excited at a different wavelength. The tri-mode SPR sensor can successfully differentiate specific binding from the non-specific binding and bulk index changes.
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Li, Yushan. "Receiver algorithms that enable multi-mode baseband terminals." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/11051.
Full textAbstract:
Wireless communications is rapidly moving towards so called 4G wireless systems. This has led to an increasing demand to develop integrated mobile terminals which have multi-mode capabilities, i.e. multiple communication systems can coexist. The central goal of this thesis is to determine appropriate structures and algorithms for multi-mode receivers that maximize flexibility without excessive compromise in performance. The work develops multi-mode terminals from the algorithm viewpoint, reducing receiver complexity by taking advantage of the commonalities among different specifications and receiver requirements. For example, the commonalities among DAB, DVB-T and HIPERLAN-2 physical layers are investigated and a common system clock is adopted for these communication systems. In addition, a receiver architecture combining sampling rate conversion and OFDM symbol synchronisation is also presented. The coexistence of WCDMA and OFDM systems from the perspective of using the same equalisation structure is elaborated; chip-level frequency domain equalisation for WCDMA forms a major part of this thesis. Simulation results verify the effectiveness of the proposed equalisation algorithms. Moreover, SC-FDE with more flexible structures, i.e. with a varying length feedback filter or without cyclic prefix, is examined. Then the importance of an accurate channel estimation for practical spread spectrum systems is emphasized. A code-multiplexed pilot sequence is used for the purpose of channel estimation in both WCDMA and CP-CDMA systems and to maintain bandwidth efficiency. System performance is improved significantly by a proposed joint iterative channel estimation and parallel interference cancellation algorithm. Finally conclusions are drawn and suggestions for further work presented.
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Rourke, Anthony. "The dynamics of multi-mode vibratory rate sensors." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269689.
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Wei, Mingrui. "Multi-Mode Stream Processing For Hopping Window Queries." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-theses/769.
Full textAbstract:
Window constraints are mechanisms to bound the tuples processed by continuous queries specified over unbounded data streams. While sliding window queries move the constraint window upon the arrival of each individual tuple, hopping window queries instead move the window by a fixed amount after some period, thus periodically refreshing their results. We observe that for large hops, techniques liked delta result updating may not be efficient -- as large portions of the tuples in the current window will be different from the previous window and thus must be maintained. On the other hand, the complete result updating technique, which has been found to be less suitable for sliding windows queries. Compute the next result based on the complete current window now can be shown to be superior in performance for some hopping windows queries. A trade-off emerges between the complete result method which has a lower per tuple processes cost but potentially processing redundant results versus the delta result method which has no redundant processing but pays a higher per tuple processing cost. On top of that, strict non-monotonic operators such as difference operator, cause premature expiration due to operator semantics. Negative tuples are needed for this kind of special expiration. Such negative tuples added extra burden to the stream engine. Thus, in streaming processing, the difference operator is typically suggested to be placed on top of the query plan despite its potential ability to reduce cardinality of the stream. With this thesis, we introduce a whole solution for hopping window query processing which includes an optimizer for generalized hopping window query optimization that exploits both processing techniques within one integrated query plan alone with query plan rewriting. First, we design the query operators to be multi-mode, that is, to be able to take either a delta or a complete result as input, and produce either a delta result or complete result as output. Then we design a cost model to be able to chose the optimal mode for each operator. Thirdly, our optimizer targets to configure each operator within a query plan to work in the suitable mode to achieve minimum overall processing costs. Last but not least, two query optimization techniques have been adopted. One explores all possibilities of pushing the difference down past joins using dynamic programming and assigning optimal mode at the same time, the other applies heuristic difference push down rule. The proposed techniques has been implemented within the WPI stream query engine, called CAPE. Finally, we show the benefit of our solution with a vast number of experimental results.
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Wingerd, Mark A. "A multi-mode spectrometer for atomic emission spectrometry." Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/37396.
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Lounsbury, William P. "Nonlinear Multi-Mode Robust Control For Small Telescopes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1417781523.
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Yin, Hang. "Introducing Mode Switch in Component-Based Software Development." Doctoral thesis, Mälardalens högskola, Inbyggda system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-28755.
Full textAbstract:
Self-adaptivity, characterized by the ability to dynamically adjust behavior at runtime, is a growing trend in the evolution of modern embedded systems. While self-adaptive systems tend to be flexible and autonomous, self-adaptivity may inevitably complicate software design, test and analysis. A strategy for taming the growing software complexity of self-adaptive systems is to partition system behaviors into different operational modes specified at design time. Such a multi-mode system can change behavior by switching between modes at runtime under certain circumstances. Multi-mode systems can benefit from a complementary approach to the software development of complex systems: Component-Based Software Engineering (CBSE), which fosters reuse of independently developed software components. However, the state-of-the-art component-based development of multi-mode systems does not take full advantage of CBSE, as reuse of modes at component level is barely addressed. Modes are often treated as system properties, while mode switches are handled by a global mode manager. This centralized mode management entails global information of all components, whereas the global information may be inaccessible in component-based systems. Another potential problem is that a single mode manager does not scale well, particularly at design time, for a large number of components and modes. In this thesis we propose a distributed solution to the component-based development of multi-mode systems, aiming for a more efficient and scalable mode management. Our goal is to fully incorporate modes in software component reuse, supporting reuse of multi-mode components, i.e., components able to run in multiple modes. We have developed a generic framework, the Mode-Switch Logic (MSL), which not only supports reuse of multi-mode components but also provides runtime mechanisms for handling mode switch. MSL includes three fundamental elements: (1) a mode-aware component model with the formal specification of reusable multi-mode software components; (2) a mode mapping mechanism for the seamless composition of multi-mode components; and (3) a mode-switch runtime mechanism which is executed by each component in isolation from its functional execution and coordinates the mode switches of different components without the need of global mode information. The mode-switch runtime mechanism has been verified by model checking in conjunction with mathematical proofs. We also provide a mode-switch timing analysis for the runtime mechanism to respect real-time requirements. MSL is dedicated to the mode aspect of a system irrespective of component execution semantics, thus independent of the choice of component models. We have integrated MSL in the ProCom component model with the extension of support for reuse of multi-mode components and distributed mode-switch handling. Although the distributed mode-switch handling of MSL is more flexible and scalable than the conventional centralized approach, when components are deployed on a single hardware platform and global mode information is available, centralized mode-switch handling is more efficient in terms of runtime overhead and mode-switch time. Hence, MSL is supplemented with a mode transformation technique to enhance runtime mode-switch efficiency by converting the distributed mechanism to a centralized mechanism. MSL together with the mode transformation technique has been implemented in a prototype tool where one can build multi-mode systems by reusing multi-mode components. The applicability of MSL is demonstrated in two proof-of-concept case studies.ARROWS - Design Techniques for Adaptive Embedded Systems
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Prinsloo, David Schalk Van der Merwe. "Multi-mode antennas for hemispherical field-of-view coverage." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97008.
Full textAbstract:
Thesis ((PhD)--Stellenbosch University, 2015.ENGLISH ABSTRACT: This dissertation proposes a multi-mode antenna element excited through a multiconductor feed. It is shown that each of the orthogonal transverse electromagnetic modes supported by the antenna feed results in a unique radiated far-field pattern that collectively allow for nearhemispherical field-of-view coverage. Three multi-mode antenna designs are presented: a dual-mode antenna, integrating a single linearly polarised dipole antenna with a co-located monopole, as well as two quad-mode antenna designs integrating two dual-polarised dipole elements with a co-located monopole element. The dual-mode antenna is excited through a balanced transmission line feed supporting both differential- and common-mode signals that, respectively, result in typical dipole-over-ground and monopole radiated far-field patterns. The quad-mode antennas are each fed through a quadraxial transmission line allowing for excitation through four orthogonal transverse electromagnetic port modes. To characterise the multi-mode response of the multi-mode antennas, generalised transformations are derived by which the multi-mode S-parameters and radiated far-fields can be calculated from the S-parameters and far-fields corresponding to single-ended excitations. These transformations are implemented to validate the response of a dual-mode and quad-mode antenna design through measurements. An equivalent network representation for active multi-mode antennas is presented, including generalised transformations relating the multi-mode signal and noise response of the low-noise amplifiers to the two-port S-parameters and noise parameters of the low-noise amplifiers. Through the use of classical beamforming algorithms, the performance of an active dual-mode and quadmode antenna is presented. In the case of the active dual-mode antenna, it is shown that through the added use of common-mode signals, a variation in sensitivity of less than 50% is achieved in the E-plane. Similarly, the additional excitation modes supported by the active quad-mode antenna is shown to result in a significant improvement in the polarimetric capabilities over the field-of-view coverage.
AFRIKAANSE OPSOMMING: Hierdie proefskrif stel ’n multimodale antenna element voor wat deur ’n multi-geleier transmissielyn gevoer word. Dit word gewys dat elk van die ortogonale transversale elektromagnetiese opwekkingsmodusse wat deur die antenna voer ondersteun word, ’n unieke vêrveld stralingspatroon skep, wat gesamentlik lei tot ’n hemisferiese gesigsveld. Drie multimodale antenna ontwerpe word voorgestel: ’n dubbelmodale antenna, waarin ’n enkel lineêrgepolariseerde dipool antenna en monopool mede-geleë word, asook twee viermodale antenna ontwerpe waarin twee dubbelgepolariseerde dipool elemente geïntegreer word met medegeleë monopool antenna elemente. Die dubbelmodale antenna word gevoer deur ’n gebalanseerde transmissielyn wat beide differensiële- en gemene-modus seine ondersteun, waar elk onderskeidelik dipool-oor-aardvlak en monopool stralingspatrone voortbring. Die viermodale antennas word elk gevoer deur vier-as transmissielyne wat vier ortogonale transversale elektromagnetiese opwekkingsmodusse ondersteun. Om die multimodale gedrag van die drie multimodale antennas te karakteriseer, word veralgemeende transformasies afgelei waardeur die multimodale strooiingsparameters asook die vêrveld stralingspatrone vanaf enkelpoort strooiingsparameters en vêrvelde bereken word. Hierdie transformasies word toegepas om die gedrag van ’n dubbel- en viermodale antenna ontwerp te karakteriseer deur metings. Ekwivalente netwerkvoorstellings vir aktiewe multimodale antennas word voorgestel, insluitend veralgemeende transformasies om die multimodale sein asook ruis gedrag van die lae-ruis versterkers betreklik te maak tot die tweepoort strooiingsparameters en ruisparameters van die laeruis versterkers. Deur gebruik te maak van klasieke bundelvormingsalgoritmes, word die gedrag van aktiewe dubbelmodale en viermodale antennas voorgestel. Vir die aktiewe dubbelmodale antenna word daar aangedui dat die gesamentlike gebruik van differensiële- en gemene-modus seine, ’n variasie in sensitiwiteit onder 50% tot gevolg het in die E-vlak. Soortgelyk word daar aangedui dat die addisionele opwekkingsmodusse wat deur die aktiewe viermodale antenna ondersteun word, tot ’n beduidende verbetering in die polarisasievermoë oor die gesigsveld lei.
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Balemarthy, Kasyapa. "Electronic Equalization of High-Speed Multi-mode Fiber Links." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16191.
Full textAbstract:
The objective of this research is to investigate low-complexity, efficient electronic equalizers to increase the data rate and possibly extend the reach of multi-mode fiber (MMF) links. Specifically, we begin by baselining the performance limits of conventional receivers. A robust, in-house mode solver was developed as part of this research and is currently being used by one of the largest fiber manufacturers in their internal R &D work.
A detailed performance assessment of the impact of decision feedback equalizers has been conducted using an extensive model of the installed fiber base. The finite-length DFE results were instrumental in influencing the IEEE 802.3aq standardization effort. In particular, we
were able to achieve a reach of 220m but the original goal of 300m was unattainable on 99% of the installed fiber base using DFEs of moderate complexity.
A low-cost equalizer that has excellent performance, the bi-directional DFE, was applied to the MMF channel for the first time. The performance of the infinite-length BiDFE was characterized without any constraints on the signal-to-noise ratio and on the receiver front-end, as has been previously done in the literature. A new joint optimization technique that helps the finite-length BiDFE perform significantly better than the infinite-length DFE was developed. It was shown that given a finite number of filter coefficients, the BiDFE utilizes them better than the conventional DFE. Furthermore, a reach of 350-400m at a data rate of 10 Gbps was shown to be feasible with equalizers of complexity similar to that currently available.
A multiple-input, multiple-output (MIMO) characterization of the MMF channel was developed through the simultaneous use of both center and
offset launch together with the two-segment photo-detector. The potential benefit of MIMO processing for MMF links was demonstrated by computing Shannon capacity bounds. It was established that the 2x2 MIMO channel performs about 1.4 dBo better than the conventional 1x1 link at 10 Gbps with practical joint launch. The MIMO scheme still has a performance improvement of 1dBo at 20 Gbps thereby indicating that 20 Gbps transmission is feasible.
Performance evaluation of multi-km MMF links was conducted using a comprehensive model that accounts for mode coupling effects. It was determined that ignoring mode coupling can result in under-estimation of the optimum DFE penalty by as much as 1~dBo for 1km links.
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Papadopoulos, Dimitrios Filippos. "A power efficient linear multi-mode CMOS radio transmitter /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18122.
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Samar, Raza. "Robust multi-mode control of high performance aero-engines." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/10006.
Full textAbstract:
This thesis describes the application of H∞ design techniques to the control of high performance aero-engines. The design study presented is practical and realistic, the work being motivated by problems that arise naturally in real engineering situations. The aero-engine is multivariable and highly nonlinear: the dynamics vary considerably with the thrust being produced, and with the altitude and forward speed of the aircraft. Moreover, there are operational constraints that must never be violated for reasons of safety: certain engine variables should always be limited to safe vales. Furthermore, not all the engine parameters to be controlled are directly measurable; instead a number of related measurements are available. A methodology is presented to choose from the available measurements, those that are preferable for feedback control. Different techniques of model reduction using balanced realizations are considered. Two illustrative examples are presented, and the methods compared in detail. Explicit state-space formulae for an H∞-based two degrees-of-freedom robust controller are derived in discrete time. The controller provides robust stability with respect to coprime factor perturbations, and a degree of robust performance in the sense of making the closed-loop system match an ideal reference model. Special attention is paid to the structure of the controller. It is shown that the controller consists of a plant observer, the reference model, and a generalized state feedback law associated with the plant and model states. Multi-mode control logic is developed to ensure that safety limits are never violated. Actual engine test results are presented for sea-level static conditions. All the different modes of operation are tested. Full flight envelope evaluation of the controller is carried out using a nonlinear engine simulation. The robust performance of the controller is demonstrated and comparisons made with existing engine control systems.
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Rai, Sheila. "Complex permittivity measurements by multi-mode microwave resonant cavity." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/11517.
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McCutcheon, Murray William. "Nonlinear optics of multi-mode planar photonic crystal microcavities." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31426.
Full textAbstract:
The nonlinear properties of multi-mode InP and Si planar photonic crystal microcavities are investigated in experiments relevant to integrated schemes for classical and quantum optical information processing. Normally incident, short laser pulses are used to coherently initialize the relative phase and amplitudes of two modes of a single-missing-hole InP microcavity. The two modes are orthogonally polarized, and separated by less than the bandwidth of the ~130 fs excitation pulses. The relative amplitudes of the two modes can be controlled by adjusting the polarization and the centre frequency of the excitation beam. Cross-polarized detection of the resonantly scattered light reveals a well-defined relative phase between the modes that is characteristic of their coherence. When the short-pulse excitation is used to coherently excite two modes in a three-hole line-defect (L3) InP microcavity, second-order harmonic radiation is observed due to the interactions of the resonant fields with the second-order nonlinear susceptibility (χ⁽²⁾) of the host InP slab. Second-harmonic and sum-frequency generated signals are observed due to the intra- and inter-mode nonlinear mixing of the microcavity fields. When a separate non-resonant pulse is focussed onto an InP microcavity, sum-frequency light is generated conditional to the resonant mode population of the microcavity. The conditionally generated signals can be tuned by tuning the frequency of the non-resonant pulse. All of the results can be explained with reference to the bulk χ⁽²⁾ properties of the InP slab. While the transient, multi-mode response of the microcavities is harnessed with the short-pulse technique, a continuous wave excitation laser exploits the local-field enhancement intrinsic to these wavelength-scale microcavities. A single-mode InP L3-microcavity with Q = 3,800 is pumped on resonance with a CW laser, and the 2D pattern of far-field second-harmonic radiation is directly imaged. The second-harmonic light is enhanced by 1000 times compared to non-resonant excitation, demonstrating integrated low-power frequency generation. The spatial pattern of the radiation is consistent with simulations based on the bulk χ⁽²⁾ tensor, and reveals the importance of scattering and material absorption of the harmonic light. Ultrafast, all-optical switching is demonstrated in a Si microcavity with a single Q = 35, 000 resonant mode. The mode is resonantly excited with a weak probe pulse, and a non-resonant 200 pJ pump pulse with a precisely controlled time delay is used to inject free-carriers above the silicon bandgap. The free-carrier dispersion shifts the mode frequency by 9 line-widths, and broadens its width by a factor of 4. When the excited mode is perturbed while it is ringing down, coherent oscillations in the spectra are observed which can be explained in terms of a model of an instantaneously perturbed harmonic oscillator, The implications for frequency conversion and for the generation of squeezed optical states are considered.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Lee, Chun-Te. "Multi-soliton solution of the two-mode KdV equation." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531973.
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O’Cull, Douglas C. "DESIGN AND PERFORMANCE OF A MULTI-MODE RECEIVER CARD." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607364.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaThis paper will discuss the design and performance of a multi-mode receiver. The receiver is designed to operate in standard VME and PC environments and will support data rates up to 20 Mbps. The paper will discuss new digital demodulation techniques that support PCM-FM, PCM-PM, FM, PM, BPSK, QPSK and O-QPSK modulation. This new demodulator also includes a built in bit sync with soft decision outputs. This paper will provide an overview on digital filtering used in the second IF filter which provides dynamic changing of the IF bandwidth.
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Hur, Joonhoi. "A highly linear and efficient out-phasing transmitter for multi-band, multi-mode applications." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42823.
Full textAbstract:
There have been many efforts to improve efficiency of transmitter while meeting stringent linearity requirement of modern communication system. Among the technology to enhance efficiency of linear transmitter, the out-phasing technologies, also called the linear amplification with nonlinear components (LINC), is considered as a promising technology. LINC has been studied long times, since it provides excellent linearity with high efficiency by allowing adopt high efficient switch-mode power amplifiers. However, The LINC transmitter has some technical challenges: linearity degradation due to amplitude and phase mismatches, efficiency degradation due to poor combining efficiency, and narrow frequency bandwidth due to output matching network of switching power amplifier.
In this thesis, some state-of-the-art techniques for solving the problems of LINC transmitters are presented. An unbalanced phase calibration technique compensates amplitude/phase mismatches between two parallel paths in the LINC system, and multi-level LINC (MLINC) and an uneven multi-level LINC (UMLINC) structure improve the overall power efficiency. And the reconfigurable Class-D switching PA enables multi-band operation with high efficiency and good linearity. With these techniques, the new multi-band out-phasing transmitter improves the efficiency without sacrificing the linearity performance.
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Chen, Ping-Shun. "Cost minimization in multi−commodity multi−mode generalized networks with time windows." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4779.
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The purpose of this research is to develop a heuristic algorithm to minimize total
costs in multi-commodity, multi-mode generalized networks with time windows
problems. The proposed mathematical model incorporates features of the congestion of
vehicle flows and time restriction of delivering commodities. The heuristic algorithm,
HA, has two phases. Phase 1 provides lower and upper bounds based on Lagrangian
relaxations with subgradient methods. Phase 2 applies two methods, early due date with
overdue-date costs and total transportation costs, to search for an improved upper bound.
Two application networks are used to test HA for small and medium-scale
problems. A different number of commodities and various lengths of planning time
periods are generated. Results show that HA can provide good feasible solutions within
the reasonable range of optimal solutions. If optimal solutions are unknown, the average
gap between lower and upper bounds is 0.0239. Minimal and maximal gaps are 0.0007
and 0.3330. If optimal solutions are known, the maximal gap between upper bounds and
optimal solutions is less than 10% ranges of optimal solutions.
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Wu, Chih-Kang, and 吳志剛. "Multi-Mode Charging Circuit." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/12917126673824776989.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
92
Charging technology is becoming more and more important since rechargeable batteries are commonly used in many applications than ever before. To facilitate various charging profiles, a battery charger with multi-mode is proposed. The charger is composed of an innovative reflex charging circuit and a controllable half-bridge converter with pulse-width-modulation. This multi-mode charger provides not only four basic functions of constant voltage (CV), constant current (CC), pulsed current (PS) and reflex charging (RX), but also the multi-stage charging with hybrid charging modes. The desired charging profile can easily be accomplished by adjusting the controllable parameters of the charger. In order to simplify the control circuit, a digital signal processor (DSP) with the associated sensors and interface circuits are used as the control kernel. By continuously monitoring the charging current and battery voltage, the charging modes can be adapted to the charging strategy. An experimental charging circuit is built and tested. The experiments in this dissertation are carried out on lead-acid batteries, Experimental results show that the charger is able to execute the charging functions of various tentative charging strategies with hybrid charging modes.
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Lu, Yu-Ting, and 盧約廷. "Multi-Band Multi-Mode Integrated Passive Modules." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/36426749992173490282.
Full textAbstract:
碩士國立交通大學
電信工程系所
94
Nowadays ,It’s the trend to integrate RF device of WLAN system ,this thesis presents a integrated module of a diplexer and two band pass filters of different bands by using LTCC technique. Design the diplexer module will meet IEEE802.11a(5.2GHz、5.7GHz) and 802.11b/g(2.4GHz) wireless LAN’s specifications. The device conforms to small size and high selectivity. In the thesis, the simulation tool is Ansoft HFSS and Microwave office. This thesis presents two structures of band pass filters, one is the LTCC three-order comb-line filter with cross-coupled capacitor, and another is two-order with two transmission zero band pass filter. The low pass filter is a complex device of constant k filter and m-derived filter. The diplexer is composite of the band pass filter and the low pass filter. Finally, the diplexer module is a composite of diplexer and two band pass filters. It has low insertion loss and high selectivity in 2.4GHz and 5GHz bands, to meet IEEE 802.11a/b/g wireless LAN’s specifications.
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Tai, Yu Feng, and 戴玉鳳. "Tunneling phenomena in few-mode and multi-mode fibers." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/03552612638305389184.
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"Multi-mode interaction among technologies." International Center for Research on the Management of Technology, Sloan School of Management, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/2602.
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Che, Su Shih, and 蘇士哲. "Solar Mobile Multi-Mode Energy Converter." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/86868976625781130123.
Full textAbstract:
碩士高苑科技大學
電子工程研究所
100
Recent mobile solar energy products provide only single power rating output. According to the patent and related literature surveys, the multi-mode energy conversion and dynamical power rating adjustment are needed for better utilization of solar cell energy. The novel solar energy converter was designed to dynamically adjust the output power rating and provide two different voltage output without using the microprocessor in this study. The energy converter consisted of the buck, boost, two-stage power rating regulating and load current detecting circuits by adopting the TI TPS54229, TPS61500 and INA202 IC Chips respectively. The design and manufacturing flow of the energy converter PCB included creating schematic diagram, routing, PCB development & etching, component mounting and soldering, and the PCB size is 62 mm 75 mm. The converter testing was carried out for the stability, startup response time and conversion efficiency by the simulated dynamic voltage curve by power supply and under the various sunny conditions to test the change of the solar energy intensity during the daytime by using high power WLED as the load. The experimental results showed the converter provides the two stable voltage output at the simulated and realistic solar energy input voltage ranged from 7 to 18V and dynamically change the other output power rating once the main loading current is increased. Under the normal sunny days, the average conversion efficiency of this novel converter was higher than 92%, the startup time was less than 25 ms and standard deviation was 0.97% that is less than the maximum error. The multi-mode solar energy converter could utilize the maximum solar energy source, and possess the merits of stability and fast startup without the microprocessor and be miniaturized for the application in the portable devices.
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Shy, Kuen-Yih, and 施昆毅. "Multi-variable Discrete Sliding Mode Control." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/14276621274076315197.
Full textAbstract:
碩士淡江大學
機械工程學系
90
A Sliding Model Control (SMC) is proposed for the temperature control of the thermal barrel in plastic molding processes. Firstly, derive a linear approximate model for the thermal barrel and treat the nonlinear term as an uncertainty or noise. Usually this uncertainty is a matched noise corresponding to the input. Since the Sliding Mode Control is robust to a matched noise, it is appropriate to design a digital sliding mode controller for a nonlinear system. Secondly, time delay of heat transferred in the thermal barrel results in oscillation at the output temperature. A grey prediction control is proposed to solve the problem caused by the time delay. According to literatures, forward grey prediction control decreases the overshoot of step response; on the other hand, backward grey prediction control increases the response speed. Finally, an on-line self-tuning SMC is developed in this paper to prevent extra work on estimation of the system parameters. Meanwhile, the adaptation of the self-tuning SMC extends the application of the controller to a large parameter range. The developed system is applied to thermal control for a plastic molding machine. Two experiments including temperature step response and trapezoid curve following are tested to evaluate the performance of the proposed methodology.
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Siao-Lung, Hwong, and 黃曉龍. "Mode Partition Noise and Chaos in a Multi-mode Nd:YVO4 Laser." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/56571552700781170035.
Full textAbstract:
碩士國立成功大學
物理學系
87
A singular value decomposition (SVD) eigenvalue spectrum is employed to explore the deterministic nature of a complex time series from a solid-state laser. With this method, the signature of chaos can be quickly identified and the noise contamination ratio can be easily estimated. It is generally believed that total output noise is always smaller than modal output noise, because of random partition of quantum fluctuation into lasing modes (i.e., mode partition noise) in multi-mode lasers. In this thesis, we show that while chaos occurs in a free-running Nd:YVO4 multi-mode microchip laser, modal output noise can be smaller than total output noise based on the SVD. The simulation results are also shown based on a set of rate equations of inhomogeneously-broadened class-B lasers which are deduced by modifying a continuous model reported for the Nd-doped fiber lasers. Similar features also can be found numerically.
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Li, Yi-ling, and 李翊鈴. "Mode Field Analysis of Single-mode Multi-core Optical Fibers based on Scalar Coupled Mode Theory." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/55973305676970651525.
Full textAbstract:
碩士國立中山大學
光電工程學系研究所
104
The recent trend in optical fiber communication is moving toward developing the multi-core fiber (MCF) with each fiber core supporting either a single mode or multi modes. It will effectively increase the bandwidth of the communications system. However, for the single-mode MCF as we reduce the cladding spacing between each core the coupling among each core increases. This will result in undesirable signal crosstalk coming from adjacent fiber cores. It is interesting to note that present theoretical prediction of the coupling strength of a single-mode MCF is a few orders of magnitude larger than experimentally measured values. We can only speculate that the coupling strength is reduced partly due to random fluctuation of relative phases among neighboring cores and partly due to polarization variation among fiber bores. Since the cross sectional area of a MCF is of several hundred/thousand wavelength square, it is impossible to conduct mode field analysis of these MCFs using commercial software using traditional mode-solving techniques such as the finite-element method or beam propagation method. In this paper, considering the small index contrast in the MCF we propose to develop a rigorous scalar coupled-mode theory (CMT) to analyze mode fields of a given single-mode MCF. The global MCF mode fields are then represented by some linear combination of linear polarized fiber mode field attributed to each single individual fiber core. In the end we have implemented Matlab codes for the MCF under CMT formulation. This program not only computes every eigen-mode of the global MCF waveguide structure it also allows us to study the mode field evolution of the single-mode MCF. As we initially turn on one of the fiber core we are able to observe that the energy gradually spread across all fiber cores according to the governing equation. When combined with new broadband MCF optical amplifiers we may see another ten-fold increase in the capacity of the optical fiber communication system with a minimum increase in cost.
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Tsai, Shih-Heng, and 蔡詩蘅. "Formal-Assisted Multi-Corner Multi-Mode Timing Analysis and Optimization Techniques." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/72199324550878090983.
Full textAbstract:
博士國立臺灣大學
電子工程學研究所
100
Timing closure has always been the biggest bottleneck in the modern VLSI design flow. To assure the correctness of circuit timing behavior, both rigorous timing analysis and powerful timing optimization are required. Traditional timing analysis techniques include static timing analysis (STA) and dynamic timing analysis (DTA). STA can be considered as a delay upper bound propagation process which simply takes the maximum delay at every circuit node, while DTA requires the input signal information (pattern) and simulate the circuit timing behaviors in a given time period with much larger run time. In the past decades, traditional STA has been a fast and decent tool to compute delay upper bound by ignoring signal interactions such as false paths and multiple input transitions. However, to achieve higher accuracy which is needed in modern design scale, such interactions must be taken into consideration. In addition, recent challenges on timing verification come from the unpredictability due to process variations (multiple corners) and the demand for low power design methodologies (multiple power modes with multiple supply voltages and operating frequencies). These multiple design scenarios, so called multi-corner multi-mode (MCMM), have significantly increased the complexities of both timing analysis and optimization. Traditional timing analysis techniques usually handle one or two scenarios at a time and require a great amount of iterations and run time to complete full circuit MCMM timing analysis. Moreover, traditional timing optimization approaches, such as dynamic-programming-based buffer insertion techniques, are unable to handle MCMM simultaneously. As a result, we need to either iteratively optimize the design one mode/corner at a time, leading to the timing convergence problem, or take a conservative approach in defining the timing constraints that ends up unsatisfiable for the original design specification. In short, MCMM timing constraints would attenuate the design margin and greatly reduce the yield. In this dissertation, we propose an integrated formal-assisted timing analysis and optimization flow which solves the MCMM issues and increases the capability of the timing verification techniques. The overall verification flow includes three parts: First, a unified Multi-Corner Multi-Mode Static Timing Analyzer (MCMM-STA) is proposed to efficiently compute the worst-case delay among various process corners; Second, a Formal-Assisted Timing Analysis (FATA) technique is applied to formally detect false paths identified by our MCMM-STA engine, consider multiple-input transitioning effects in delay calculations, and generate input transition patterns for true critical paths in timing debugging and post-layout simulations; And third, a novel Semi-Formal Buffer Insertion (SFBR) algorithm is devised to compute a minimum-cost buffer placement for the MCMM timing constraints based on the results of our MCMM-STA and FATA.