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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

A 26 GHz Phase-Locked Loop Frequency Multiplier in 0.18-um CMOS

Carr, John 25 April 2009 (has links)
This thesis presents the analysis, design and characterization of an integrated high-frequency phase-locked loop (PLL) frequency multiplier. The frequency multiplier is novel in its use of a low multiplication factor of 4 and a fully differential topology for rejection of common mode interference signals. The PLL is composed of a voltage controlled oscillator (VCO), injection-locked frequency divider (ILFD) for the first divide-by-two stage, a static master-slave flip-flop (MSFF) divider for the second divide-by-two stage and a Gilbert cell mixer phase detector (PD). The circuit has been fabricated using a standard CMOS 0.18-um process based on its relatively low cost and ready availability. The PLL frequency multiplier generates an output signal at 26 GHz and is the highest operational frequency PLL in the technology node reported to date. Time domain phase plane analysis is used for prediction of PLL locking range based on initial conditions of phase and frequency offsets. Tracking range of the PLL is limited by the inherent narrow locking range of the ILFD, and is confirmed via experimental results. The performance benefits of the fully differential PLL are experimentally confirmed by the injection of differential- and common-mode interfering signals at the VCO control lines. A comparison of the common- and differential-mode modulation indices reveals that a common mode rejection ratio (CMRR) of greater than 20 dB is possible for carrier offset frequencies of less than 1 MHz. Closed-loop frequency domain transfer functions are used for prediction of the PLL phase noise response, with the PLL being dominated by the reference and VCO phase noise contributions. Regions of dominant phase noise contributions are presented and correlated to the overall PLL phase noise performance. Experimental verifications display good agreement and confirm the usefulness of the techniques for PLL performance prediction. The PLL clock multiplier has an operational output frequency of 26.204 to 26.796 GHz and a maximum output frequency step of 16 MHz. Measured phase noise at 1 MHz offset from the carrier is -103.9 dBc/Hz. The PLL clock multiplier core circuit (VCO/ILFD/MSFF Divider/PD) consumes 186 mW of combined power from 2.8 and 4.3 V DC rails. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2009-04-24 11:31:35.384
342

企業結合效率抗辯之法律經濟分析-以水平結合為中心-

張建隆 Unknown Date (has links)
反壟斷法(我國為公平交易法)上的效率抗辯,是指經營者通過證明結合的效率效果足以抵消或超過反競爭效果而取得反壟斷法豁免。“減損競爭”和“促進效率”這兩大因素的權衡是企業結合反壟斷控制的核心內容。 第一章為引言部分,提出本文的研究動機,並對研究方法、研究限制及論文大綱進行簡要介紹。在第二章介紹效率抗辯定義,及反壟斷法視野下普遍被接受的主要效率類型。第三章對效率抗辯制度在歐美國家的發展作了回顧。第四章則是利用經濟分析方法,計算反競爭效果,再比較分析實質性減少競爭標準和嚴重妨礙有效競爭標準之差異。第五章分三部份,第5.1章提及普遍被採納的效率抗辯模式,主要係一體分析模式、抵消分析模式和混合分析模式三種。並建議基於我國國情和《公平交易法》的相關規定,我國宜採用混合分析模式。第5. 2章就效率抗辯制度的適用標準而言,主要有價格標準、消費者剩餘標準、總剩餘標準和權重平衡標準。第5. 3章建議確立效率抗辯制度的證明標準、證明方法。尤其,就效率抗辯制度的適用條件而言,主要有效率為集中所特有、效率的及時性、效率的可證實性、在壟斷或接近壟斷的集中案件不應適用等要件。第六章建議我國明確建立安全港標準,凡屬於安全港範圍的結合不再作進一步審查。第七章綜合上述的結論,試著對我國效率抗辯制度建立提供建議 。 關鍵字:效率抗辯、事業結合、實質性減少競爭標準、嚴重妨礙有效競爭標準、抵消分析、一體分析、混合分析、價格標準、消費者福利標準、總剩餘標準、權重平衡標準 / The efficiency plea on the antitrust law refers that the intensified efficiency effect proved by the operator is sufficient to set off or stronger than the anti-competition effect so as to be exempted by the antitrust law. Competition impairment and efficiency promotion are two factors need to be traded off during the anti-monopoly control on concentration for business operators. Chapter One presents the motive , approach, framework, scope and limitations of the paper. Chapter Two introduces the definition of efficiency and the main types of efficiency which includes production efficiency, allocative efficiency, dynamic efficiency and other efficiencies. Chapter Three provides a brief history of efficiency plea practices in Europe and the United States . Chapter 4 tries to compare the Substantial Lessening of Competition test (SLC) with Significantly Impedes Effective Competition test (SIEC ) standards and try to prove the SIEC is suitable for our country. Chapter 4 also attempts to analyze anti-competitive effects of mergers by using economic analysis methods. Chapter Five is divided into three sections. Section one analyzes the main types of efficiency defense system models, including the integrated analysis model, offset analysis model and mixed analysis model. Considering the actual situation in our country and in accordance with regulations by the Antitrust Law of Taiwan, a mixed analysis mode is suggested for application. Section two focuses on the welfare standards of price standard, consumer welfare standard, the total surplus standard and the balancing weights standard. Section three recommends that standard of proof and method of proof and types of application conditions shall be established. Especially, the main types of application conditions are efficiency specific to concentration, the timeliness of the efficiency, the verifiability of the efficiency and whether the efficiency defense system is applied in the situation of near monopoly. Chapter Six defines the relevant market and suggest Critical loss analysis should be introduced for the relevant market definition. Chapter Six also suggests to adopt the " strong safe harbor" standard which means that once undertakings belong to the safe harbor range,they will no longer be subject to further review. The final chapter tries to offer some suggestions on the establishment of efficiency defense in Taiwan . Key words: efficiency plea, concentration of undertakings, the Substantial Lessening of integrated analysis model, offset analysis model, mixed analysis model, price standard, consumer welfare standard, the total surplus standard, the balancing weights standard
343

Σχεδιασμός αλγορίθμων προσαρμοστικής διαμόρφωσης και αντιμετώπισης θορύβου φάσης σε ασύρματα τηλεπικοινωνιακά συστήματα πολλαπλών φερουσών

Δαγρές, Ιωάννης 08 July 2011 (has links)
Αντικείμενο της παρούσας διδακτορικής διατριβής είναι η μελέτη και ο σχεδιασμός καινοτόμων αλγορίθμων φυσικού επιπέδου σε ασύρματα συστήματα επικοινωνίας που χρησιμοποιούν διαμόρφωση με πολύπλεξη συχνότητας ορθογωνίων φερουσών (Orthogonal Frequency Division Multiplexing - OFDM). Η έρευνα επικεντρώθηκε σε δύο κατηγορίες προβλημάτων, στον σχεδιασμό αλγορίθμων προσαρμοστικής διαμόρφωσης καθώς και αλγορίθμων αντιμετώπισης ισχυρού θορύβου φάσης. Αναπτύχθηκαν αλγόριθμοι εκτίμησης φάσης με γραμμική πολυπλοκότητα, μέσω ενός καινούργιου εναλλακτικού μοντέλου περιγραφής του συστήματος. Το μοντέλο αυτό επιτρέπει την επέκταση των κλασικών αλγορίθμων εκτίμησης της κοινής φάσης με στόχο την εκτίμηση του συνολικού διανύσματος θορύβου φάσης. Επιπλέον, η τεχνική διαγώνιας φόρτωσης (diagonal-loading) προσαρμόστηκε κατάλληλα για τη βελτίωση σύγκλισης της προτεινόμενης λύσης. Τέλος, προτάθηκε και αξιολογήθηκε ένα συνολικό σύστημα OFDM όπου η εκτίμηση του καναλιού, της διαταραχής φάσης και των δεδομένων βασίζονται στο κριτήριο ελαχίστων τετραγώνων, διατηρώντας έτσι τη συνολική πολυπλοκότητα σε χαμηλά επίπεδα. Στο πλαίσιο του σχεδιασμού αλγορίθμων προσαρμοστικής διαμόρφωσης προτείνεται ένα γενικό μοντέλο περιγραφής απόδοσης συστήματος ικανό να περιγράψει τα αναπτυσσόμενα πρωτόκολλα μετάδοσης. Η πρόταση αυτή εντάσσεται στην οικογένεια των τεχνικών ισοδύναμης σηματοθορυβικής απεικόνισης (Εffective SNR Μapping - ESM). Χρησιμοποιώντας τις τεχνικές ESM και κατάλληλους περιορισμούς στην παραμετροποίηση των μεταβλητών μετάδοσης, αναπτύχθηκαν αλγόριθμοι προσαρμοστικής διαμόρφωσης χαμηλής πολυπλοκότητας που ικανοποιούν διαφορετικά κριτήρια βελτιστοποίησης. Επιπρόσθετα, προτείνεται ένα γενικό πλαίσιο για τον σχεδιασμό αλγορίθμων προσαρμοστικής διαμόρφωσης, χρησιμοποιώντας προσεγγιστικά μοντέλα απόδοσης. Ορίστηκαν οι κατάλληλες μετρικές για την ποσοτικοποίηση της σπατάλης ενέργειας που επιφέρει η χρήση προσεγγιστικών μοντέλων. Μελετήθηκε η επίδραση της καθυστέρησης ανατροφοδότησης πληροφορίας καναλιού στους αλγορίθμους και παρήχθησαν κατάλληλα μοντέλα περιγραφής απόδοσης που συμπεριλαμβάνουν το χρόνο καθυστέρησης. Το συνολικό αποτέλεσμα της εργασίας είναι αλγόριθμοι που καταφέρνουν υψηλή απόδοση συστήματος, με χαμηλή πολυπλοκότητα, κάτι το οποίο τους κάνει υλοποιήσιμους σε ρεαλιστικά συστήματα. / The objective of this thesis is to study and develop novel, low complexity physical layer algorithms for Orthogonal Frequency Division Multiplexing (OFDM) based communication systems. The study aims at two algorithmic categories, namely adaptive modulation and coding and compensation of severe phase noise (PHN) errors. A parameterized windowed least-squares (WLS) decision directed phase error estimator is proposed via proper (alternative) system modeling, applied to both channel estimation and data detection stage in OFDM systems. The window is optimized so as to minimize the post-compensation error variance (PCEV) of the residual phase, analytically computed for arbitrary PHN and frequency offset (FO) models. Closed-form expressions for near-optimal windows are derived for zero-mean FO, Wiener and first-order autoregressive PHN models, respectively. Furthermore, the diagonal-loading approach is properly employed, initially proposed for providing robustness to a general class of estimators in the presence of model mismatch, to enhance convergence of the iterative estimation scheme, in those high-SNR regions where the effect of data decision errors dominates performance. In the proposed OFDM scheme, channel, IFO estimation and data equalization are also based on the LS criterion, thus keeping the overall system complexity low. A generic performance description model is proposed and used for AMC algorithmic design, capable of describing most of current and under preparation communication protocols. This model proposition is incorporated to a larger family of performance modelling techniques named Effective SNR Mapping techniques (ESM). Using the ESM techniques and proper parameter adaptation constraints, a number of low-complexity AMC algorithms are developed under a chosen set of optimization scenarios. A framework for the design of AMC algorithms using approximate performance description models is proposed. Specific bounds are derived for quantifying the power loss when using approximate models. The effect of outdated channel state information is also studied by statistically characterizing the effective SNR at the receiver. This description allows parameter adaptation under mobility scenarios. The main value of this collective procedure is the development of low complexity- high performance algorithms, implementable on pragmatic OFDM systems.
344

Transceiver Design Based on the Minimum-Error-Probability Framework for Wireless Communication Systems

Dutta, Amit Kumar January 2015 (has links) (PDF)
Parameter estimation and signal detection are the two key components of a wireless communication system. They directly impact the bit-error-ratio (BER) performance of the system. Several criteria have been successfully applied for parameter estimation and signal detection. They include maximum likelihood (ML), maximum a-posteriori probability (MAP), least square (LS) and minimum mean square error (MMSE) etc. In the linear detection framework, linear MMSE (LMMSE) and LS are the most popular ones. Nevertheless, these criteria do not necessarily minimize the BER, which is one of the key aspect of any communication receiver design. Thus, minimization of BER is tantamount to an important design criterion for a wireless receiver, the minimum bit/symbol error ratio (MBER/MSER). We term this design criterion as the minimum-error-probability (MEP). In this thesis, parameter estimation and signal detection have been extensively studied based on the MEP framework for various unexplored scenar-ios of a wireless communication system. Thus, this thesis has two broad categories of explorations, first parameter estimation and then signal detection. Traditionally, the MEP criterion has been well studied in the context of the discrete signal detection in the last one decade, albeit we explore this framework for the continuous parameter es-timation. We first use this framework for channel estimation in a frequency flat fading single-input single-output (SISO) system and then extend this framework to the carrier frequency offset (CFO) estimation of multi-user MIMO OFDM system. We observe a reasonably good SNR improvement to the tune of 1 to 2.5 dB at a fixed BER (tentatively at 10−3). In this context, it is extended to the scenario of multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) or MIMO-OFDM with pa-rameter estimation error statistics obtained from LMMSE only and checked its effect at the equalizer design using MEP and LMMSE criteria. In the second exploration of the MEP criterion, it is explored for signal detection in the context of MIMO-relay and MIMO systems. Various low complexity solutions are proposed to alleviate the effect of high computational complexity for the MIMO-relay. We also consider various configurations of relay like cognitive, parallel and multi-hop relaying. We also propose a data trans-mission scheme with a rate of 1/Ns (Ns is the number of antennas at the transmitter) with the help of the MEP criterion to design various components. In all these cases, we obtain considerable BER improvement compared to the existing solutions.
345

Evaluation non destructive des matériaux de construction par technique électromagnétique aux fréquences radar : modélisation et expérimentation en laboratoire

Mai, Tien chinh 10 December 2015 (has links)
Les structures en béton armé ou en bois se dégradent sous des actions mécaniques et climatiques. Les propriétés physiques et mécaniques de ces matériaux sont liées aux conditions d'exposition et à leurs variations. L’évaluation non destructive de ces propriétés en amont des dégradations est une nécessité pour les maîtres d'ouvrages afin de prédire la durée de vie des structures dans un contexte de gestion durable du patrimoine bâti. La présence d’eau dans les pores du béton est un facteur qui facilite la pénétration des agents agressifs (dioxyde de carbone, chlorures, etc. responsables de l’initiation de pathologies comme la corrosion des aciers). Pour le cas du matériau bois, les causes les plus fréquentes des détériorations sont souvent d’origine biologiques (champignons et insectes). L’humidité est également reconnue comme une des conditions les plus importantes pour le développement de ces attaques. Il est donc nécessaire d’évaluer et de quantifier la variation spatiale de l’humidité dans ces matériaux de construction pour limiter les actions de réparation. Le système radar (Ground Penetrating Radar, « GPR ») est un outil d’auscultation des matériaux totalement non destructif, rapide, compact et sans contact. Cette technique est basée sur la propagation des ondes électromagnétiques. Cette propagation est fortement liée à la permittivité et la conductivité du matériau qui sont très sensibles aux variations de l’humidité. L’objectif de cette thèse est double : d’une part, modéliser l’effet des variations de l’humidité dans un matériau homogène, multi-couches ou avec gradient, et d’autre part, de quantifier expérimentalement l’effet d’un gradient d’humidité sur le béton et celui de l’anisotropie sur le bois. Pour cela, un modèle analytique a été développé en se basant sur la notion des lois de mélange (ajustées sur des mesures expérimentales de la permittivité en prenant en compte l’effet de la dispersion fréquentielle) et sur la propagation d’une onde plane. Une simulation numérique a permis d’apprécier l’effet d’un gradient et d’un milieu anisotropique sur la vitesse de propagation des ondes radar. La phase expérimentale a été effectuée sur un matériau modèle homogène et isotrope comme le sable pour comparer les différentes méthodes de mesure de la vitesse de l’onde directe. Une analyse fréquentielle de l’atténuation a été également étudiée pour évaluer la dispersion de l’atténuation dans un milieu considéré comme homogène. La deuxième partie de l’expérimentation a consisté à suivre par mesures radar le séchage d’une dalle en béton instrumentée par capteurs d’humidité. Enfin, une campagne expérimentale sur des échantillons en bois de deux essences (Pin et Epicéa) soumis à des humidités variables entre 0 et 50% a été menée. La phase de modélisation et de simulation a montré que la dispersion fréquentielle est significative seulement dans le cas d’un béton humide à forte salinité et que l’anisotropie et le gradient ont un effet significatif sur la propagation. La phase expérimentale a montré que dans le cas d’un matériau homogène, la vitesse est indépendante de la distance émetteur-récepteur, et qu’elle est variable dans le cas d’un béton soumis à un gradient d’humidité. Enfin, les essais sur le bois montrent que la partie réelle de sa permittivité est croissante en fonction de l’humidité. Le contraste de permittivité entre direction longitudinale et transversale (tangentielle ou radiale) est négligeable à l’état sec du matériau et commence à être significatif à partir de la saturation des fibres. Cela permet de privilégier la direction longitudinale à la direction transversale pour évaluer l’humidité des structures en bois. / The reinforced concrete or the timber structures are degraded under mechanical and climatic actions. Physical and mechanical properties of these materials are linked to outdoor exposure conditions and their variations. The early non-destructive evaluation of these properties before the initiation of degradations is a need for masters of structures in order to predict the service life of the structures in a context of sustainable management of the built heritage. The presence of water in the pores of the concrete is a factor which facilitates the penetration of aggressive agents (carbon dioxide, chlorides, etc. responsible of the initiation of pathologies such as steel corrosion). In the case of wood material, the most common causes of damage are often of biological origin (fungi and insects). Moisture is also recognized as one of the most important conditions for the development of these attacks. It is therefore necessary to evaluate and quantify the spatial variation of the humidity in the building materials to limit repair actions. The GPR system (Ground Penetrating Radar) is an auscultation tool of materials which is completely non-destructive, fast, compact, and contactless. This technique is based on the propagation of electromagnetic waves. This propagation is strongly linked to the permittivity and the conductivity of the material that are highly sensitive to changes in humidity. The objective of this thesis is twofold: first, modelling the effect of moisture variation in a homogeneous material, multi-layers or with gradient, and secondly, to experimentally quantify the effect of a moisture gradient on the concrete and the effect of the anisotropy (case of wood material). An analytical model has been developed based on the concept of mixing laws (Fitted on experimental measurements of the permittivity by taking into account the effect of the frequency dispersion) and the propagation of a plane wave. A numerical simulation was used to assess the effects of a gradient and the effect of an anisotropic medium on the propagation velocity of the radar waves. The experimental phase was performed on a homogeneous and isotropic model material such as sand to compare different measurement methods of the velocity of the direct wave. A frequency analysis of the attenuation was also examined to evaluate the dispersion of the attenuation in a considered homogeneous medium. The second part of the experiment was to monitor, by radar measurements, the drying of a concrete slab instrumented by humidity sensors. Finally, an experimental campaign on samples of two species of wood (Pine and Spruce) with different moisture content between 0 and 50% was conducted. The modelling and simulations phase has shown that the frequency dispersion is significant only in the case of wet concrete with a high salinity content. The anisotropy and the gradient have a significant effect on the spread. The experimental phase showed that in the case of a homogeneous material, the speed is independent of the offset (distance between transmitter and receiver), and it varies in the case of concrete with a moisture gradient. Finally, tests on the timber indicate that the real part of its permittivity increases as a function of moisture. The contrast between longitudinal and transverse direction (tangential or radial) is negligible in the dry state of the material and begins to be very significant from the fiber saturation point. It indicates that the longitudinal direction, instead of the transverse direction, is more convenient to measure the moisture of wood structures.
346

Petrophysics and fluid mechanics of selected wells in Bredasdorp Basin South Africa

Ile, Anthony January 2013 (has links)
Magister Scientiae - MSc / Pressure drop within a field can be attributed to several factors. Pressure drop occurs when fractional forces cause resistance to flowing fluid through a porous medium. In this thesis, the sciences of petrophysics and rock physics were employed to develop understanding of the physical processes that occurs in reservoirs. This study focussed on the physical properties of rock and fluid in order to provide understanding of the system and the mechanism controlling its behaviour. The change in production capacity of wells E-M 1, 2, 3, 4&5 prompted further research to find out why the there will be pressure drop from the suits of wells and which well was contributing to the drop in production pressure. The E-M wells are located in the Bredasdorp Basin and the reservoirs have trapping mechanisms of stratigraphical and structural systems in a moderate to good quality turbidite channel sandstone. The basin is predominantly an elongated north-west and south-east inherited channel from the synrift sub basin and was open to relatively free marine circulation. By the southwest the basin is enclose by southern Outeniqua basin and the Indian oceans. Sedimentation into the Bredasdorp basin thus occurred predominantly down the axis of the basin with main input direction from the west. Five wells were studied E-M1, E-M2, E-M3, E-M4, and E-M5 to identify which well is susceptible to flow within this group. Setting criteria for discriminator the result generated four well as meeting the criteria except for E-M1. The failure of E-M1 reservoir well interval was in consonant with result showed by evaluation from the log, pressure and rock physics analyses for E-M1.iv Various methods in rock physics were used to identify sediments and their conditions and by applying inverse modelling (elastic impedance) the interval properties were better reflected. Also elastic impedance proved to be an economical and quicker method in describing the lithology and depositional environment in the absence of seismic trace.
347

Le recours au principe de compensation écologique dans les politiques publiques en faveur de la biodiversité : enjeux organisationnels et institutionnels : cas des écosystèmes aquatiques marins et continentaux / Organizational and institutional issues of implementing biodiversity offsets policies : a case study of continental and offshore wetlands

Vaissière, Anne-Charlotte 27 November 2014 (has links)
La compensation écologique, envisagée dans le respect de la séquence éviter-réduire-compenser les impacts, cherche à apporter des réponses à la crise actuelle d’érosion de la biodiversité. L’objectif de la thèse est de comprendre quels sont les enjeux organisationnels et institutionnels de la mise en œuvre du principe de compensation écologique pour les impacts sur les écosystèmes aquatiques marins et continentaux en Europe et aux Etats-Unis. La thèse mobilise le cadre théorique de l’économie néo-institutionnelle. Les organisations de type hiérarchique (compensation au cas par cas) ont pour principales limites d’avoir une efficacité écologique discutable et de ne pas permettre le suivi et le contrôle des mesures compensatoires ce qui conduit souvent à ce que la compensation ne soit pas ou peu mise en œuvre. Aux Etats-Unis, les banques de compensation consistent en une réponse anticipée et mutualisée aux dommages à l’environnement. Il s’agit d’une forme organisationnelle alternative hybride fortement régulée à mi-chemin entre la hiérarchie et le marché. Cependant, les acteurs ont des stratégies collectives et individuelles qui engendrent des négociations ayant des conséquences sur les enjeux de développement économique et de maintien des objectifs de conservation de la biodiversité. Le système des banques de compensation crée un double phénomène de redistribution des coûts de transaction et de diminution de ceux-ci mais il semble que l’évolution de l’ensemble du cadre d’application de la compensation écologique américain permet aujourd’hui une complémentarité institutionnelle entre ces deux formes organisationnelles plutôt qu’une disparition des formes hiérarchiques. / Biodiversity offset, as the last step of the mitigation hierarchy (avoid/reduce/offset), aims to address the current biodiversity loss crisis. The main goal of this PhD, which relies on the new institutional economics approach as a theoretical framework, is to understand the organizational and institutional issues of implementing biodiversity offsets policies for impacts on continental and offshore wetlands in Europe and the United-States. Hierarchical organizations (i.e. permittee responsible mitigation) often lead to little to no implementation of biodiversity offsets because the ecological effectiveness of case-by-case compensatory measures is unproven and the monitoring and control of numerous measures are difficult. In the United-States, the mitigation banking system aims to compensate for multiple small impacts on wetlands by carrying out restoration projects on fewer but larger wetland areas in order to reach the goal of no net loss of biodiversity. This hybrid organizational form is highly regulated and therefore stands halfway between hierarchical and market organizations. However, actors have individual and collective strategies that generate negotiations with consequences on economic development and biodiversity conservation stakes. The mitigation banking system leads to a decrease of transaction costs and a change of the actors bearing them. It seems that the evolution of the whole framework of biodiversity offsets policy implementation in the United-States leans toward an institutional complementarity between these two organizational forms rather than a disappearance of hierarchical organizations.
348

Získávání dat z kamer / Controlling of camera

Tylš, Ladislav January 2009 (has links)
This thesis describes the principles of making application which is able to set and control camera. The first part describes basic camera connections and it explains definition and specification of camera’s features. The second part of my thesis describes implementation of application, which can use more cameras to image preview, image acquisition and to simply set of camera’s features. To implement the applications we can use MATLAB and C++BUILDER uses opencv libraries.
349

Compact Multi-Coil Inductive Power Transfer System with a Dynamic Receiver Position Estimation

Bouattour, Ghada 07 April 2022 (has links)
Inductive power transfer (IPT) systems with tolerance to the lateral misalignment are advantageous for enhancing the transmitted power, usability and security of the system. In this thesis, a misalignment tolerant multi-coil design is proposed to supply stationary and dynamic battery-free wireless devices. A compact architecture composed of individually switchable 3 layers of printed coils arranged with overlap for excellent surface coverage. A hybrid architecture based on three compact AC supply modules reduces the supply circuit complexity on the sending Seite 2 von 4side. It detects the position of the receiver coil quickly, controls the activation of the transmitting coils and estimates the next receiver position. The proposed architecture reduces the circuit footprint by a factor of 62% compared to common architectures. A transmitter coil activation strategy is proposed based on the detection of the transmitting coils voltage and communication between sending side and receiving side to detect devices to supply nature and position and to differentiate them from other conductive objects in the sending area to the supplying security. The experimental results prove that the proposed architecture has a good performance for different trajectories when the device speed does not exceed 15 mm/s. Besides, the maximum detection time for the initial device position is about 1.6 s. The maximal time interval to check the transmitter coils is around 0.7 s.:1. INTRODUCTION 2. THEORETICAL BACKGROUND 3. STATE OF THE ART OF MULTI-COIL IPT SYSTEMS 4. NOVEL DESIGN OF A MULTI-COIL IPT SYSTEM 5. MULTI-COIL ACTIVATION PROCEDURE 6. EXPERIMENTAL INVESTIGATIONS 7. CONCLUSION AND OUTLOOK / Induktive Energieübertragungssysteme (IPT) mit Toleranz gegenüber seitlichem Versatz sind vorteilhaft, um die übertragene Leistung, die Nutzbarkeit und die Sicherheit des Systems zu verbessern. In dieser Arbeit wird ein versatztolerantes Multispulen-Design vorgeschlagen, um stationäre und dynamische batterielose drahtlose Geräte zu versorgen. Die kompakte Architektur besteht aus 3 einzeln schaltbaren Schichten gedruckter Spulen, die überlappend angeordnet sind, um eine hervorragende Oberflächenabdeckung zu gewährleisten. Eine hybride Architektur, die auf drei kompakten AC-Versorgungsmodulen basiert, reduziert die Komplexität der Versorgungsschaltung auf der Senderseite. Sie erkennt die Position der Empfängerspule schnell, steuert die Aktivierung der Sendespulen und schätzt die nächste Empfängerposition. Die vorgeschlagene Architektur reduziert den Platzbedarf der Schaltung um einen Faktor von 62 % im Vergleich zu herkömmlichen Architekturen. Es wird eine Aktivierungsstrategie für die Sendespulen vorgeschlagen, die auf der Erkennung der Spannung der Sendespulen und der Kommunikation zwischen Sende- und Empfangsseite basiert, um die Art und Position der zu versorgenden Geräte zu erkennen und sie von anderen leitfähigen Objekten im Sendebereich zu unterscheiden. Die experimentellen Ergebnisse zeigen, dass die vorgeschlagene Architektur eine gute Leistung für verschiedene Trajektorien hat, wenn die Geschwindigkeit der Geräte 15 mm/s nicht überschreitet. Außerdem beträgt die maximale Erkennungszeit für die anfängliche Geräteposition etwa 1,6 s. Das maximale Zeitintervall für die Überprüfung der Senderspulen beträgt etwa 0,7 s.:1. INTRODUCTION 2. THEORETICAL BACKGROUND 3. STATE OF THE ART OF MULTI-COIL IPT SYSTEMS 4. NOVEL DESIGN OF A MULTI-COIL IPT SYSTEM 5. MULTI-COIL ACTIVATION PROCEDURE 6. EXPERIMENTAL INVESTIGATIONS 7. CONCLUSION AND OUTLOOK
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Performance Analysis and PAPR Reduction Techniques for Filter-Bank based Multi-Carrier Systems with Non-Linear Power Amplifiers / Réduction du PAPR pour les systèmes utilisant la modulation FBMC/OQAM en présence d’amplificateur de puissance non linéaire

Bulusu, Sri Satish Krishna Chaitanya 29 April 2016 (has links)
Cette thèse a été effectuée dans le cadre du projet européen FP7 EMPHATIC (Enhanced Multicarrier Techniques for Professional Ad-Hoc and Cell-Based Communications). Plusieurs universités européennes et deux partenaires industriels: THALES Communications Security et CASSIDIAN ont participé à ce projet. L'objectif de ce projet est de développer, d'évaluer et de démontrer les apports des techniques multi-porteuses avancées, permettant une meilleure utilisation des bandes de fréquences radio existantes en fournissant des services de données à large bande, en coexistence avec les services traditionnels à bande étroite. Le projet porte sur l'application de radiocommunications mobiles professionnelles (Professional Mobile Radio : PMR). L'idée principale de ce projet est d'analyser la viabilité des systèmes à large bande utilisant des bancs de filtres (Filter Bank Multi Carrier : FBMC) conjointement avec une modulation d'amplitude en quadrature avec décalage (Offset Quadrature Amplitude Modulation : OQAM) dans le cadre de la 5ème génération (5G) des systèmes radio-mobiles. La modulation FBMC-OQAM se positionne comme candidate potentielle pour les futurs systèmes de communication. Cette modulation avancée offre de nombreux avantages tels que l’excellente localisation fréquentielle de sa densité spectrale de puissance (DSP), une robustesse au bruit de phase, aux décalages de fréquence ainsi qu’à l’asynchronisme entre les utilisateurs. Ces atouts, la rendent plus attrayant qu’OFDM pour l’application PMR, la radio cognitive (CR) et la 5G. Cependant, comme toute autre technique de modulation muti-porteuses, FBMC-OQAM souffre d’un facteur de crête ou d’un PAPR (pour Peak to Average Power Ratio) élevé. Lorsque l'amplificateur de puissance (AP), utilisé au niveau de l’émetteur, est opéré proche de sa zone non-linéaire (NL), ce qui est le cas dans la pratique, la bonne localisation fréquentielle de la DSP du système FBMC/OQAM est sérieusement compromise, en raison des remontées spectrales. Le premier objectif de cette thèse est de prédire l'étendue des remontées spectrales dans les systèmes FBMC-OQAM, introduites par la non-linéarité AP. Le deuxième objectif de ce travail est de proposer des techniques, pour les systèmes FBMC-OQAM, permettant la réduction du PAPR et la linéarisation de l’AP, afin d'atténuer les effets NL. L’utilisation des cumulants, a permis de prédire les remontées spectrales pour les signaux FBMC-OQAM après amplification NL. En outre, certains algorithmes de réduction du PAPR, basées sur des approches probabilistes et des techniques d'ajout de signaux, ont été proposés. La capacité de coexistence du système à large bande utilisant FBMC-OQAM avec des systèmes PMR à bande étroite en présence de PA a été analysée et il a été démontré que la coexistence est possible, à condition qu'il y est une bonne combinaison entre le recul du signal à l’entrée de l’AP (Input Back-Off : IBO), la réduction du PAPR et la linéarisation de l’AP. Enfin, une nouvelle technique de linéarisation de l’AP a été proposée pour le système FBMC-OQAM. / This thesis is part of the European FP7 EMPHATIC project (Enhanced Multicarrier Techniques for Professional Ad-Hoc and Cell-Based Communications) including various European universities and two main industrial partners: THALES Communications Security and CASSIDIAN. The EMPHATIC objective is to develop, evaluate and demonstrate the capability of enhanced multi-carrier techniques to make better use of the existing radio frequency bands in providing broadband data services in coexistence with narrowband legacy services. The project addresses the Professional Mobile Radio (PMR) application. The main idea is to analyze the viability of broadband systems based on filter-bank multi-carrier (FBMC) clubbed with o ffset quadrature amplitude modulation (OQAM) in the context of the future 5th Generation (5G) radio access technology (RAT). Increasingly, the FBMC-OQAM systems are gaining appeal in the probe for advanced multi-carrier modulation (MCM) waveforms for future communication systems. This advanced modulation scheme o ers numerous advantages such as excellent frequency localization in its power spectral density (PSD), a robustness to phase noise, frequency off sets and also to the multi-user asynchronism; making it more appealing than OFDM for PMR, cognitive radio (CR) and 5G RAT. However, like any other MCM technique, FBMC-OQAM suff ers from high PAPR. When the power amplifi er (PA) non-linearity, which is realistic radio-frequency impairment, is taken into account; the good frequency localization property is severely compromised, due to the spectral regrowth. The first objective of this PhD thesis is, to predict the extent of the spectral regrowth in FBMC-OQAM systems, due to the PA non-linearity. The second objective is to probe techniques for FBMC-OQAM systems, such as PAPR reduction and PA linearization, in order to mitigate the NL eff ects of PA. By cumulant analysis, spectral regrowth prediction has been done for FBMC-OQAM systems. Also, some algorithms for PAPR reduction, which are based on probabilistic approach and adding signal methods, have been proposed. The coexistence capability of the FBMC-OQAM based broadband system with the narrowband PMR systems in the presence of PA has been analyzed and it has been found that coexistence is possible, provided there is a symbiotic combination of PA Input Back-off (IBO), PAPR reduction and PA linearization. Finally, a novel PA linearization technique has been proposed for FBMC-OQAM.

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