Dissertations / Theses on the topic 'Channel compensation'
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Neville, Katrina Lee, and katrina neville@rmit edu au. "Channel Compensation for Speaker Recognition Systems." RMIT University. Electrical and Computer Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080514.093453.
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This thesis attempts to address the problem of how best to remedy different types of channel distortions on speech when that speech is to be used in automatic speaker recognition and verification systems. Automatic speaker recognition is when a person's voice is analysed by a machine and the person's identity is worked out by the comparison of speech features to a known set of speech features. Automatic speaker verification is when a person claims an identity and the machine determines if that claimed identity is correct or whether that person is an impostor. Channel distortion occurs whenever information is sent electronically through any type of channel whether that channel is a basic wired telephone channel or a wireless channel. The types of distortion that can corrupt the information include time-variant or time-invariant filtering of the information or the addition of 'thermal noise' to the information, both of these types of distortion can cause varying degrees of error in information being received and analysed. The experiments presented in this thesis investigate the effects of channel distortion on the average speaker recognition rates and testing the effectiveness of various channel compensation algorithms designed to mitigate the effects of channel distortion. The speaker recognition system was represented by a basic recognition algorithm consisting of: speech analysis, extraction of feature vectors in the form of the Mel-Cepstral Coefficients, and a classification part based on the minimum distance rule. Two types of channel distortion were investigated: Convolutional (or lowpass filtering) effects Addition of white Gaussian noise Three different methods of channel compensation were tested: Cepstral Mean Subtraction (CMS) RelAtive SpecTrAl (RASTA) Processing Constant Modulus Algorithm (CMA) The results from the experiments showed that for both CMS and RASTA processing that filtering at low cutoff frequencies, (3 or 4 kHz), produced improvements in the average speaker recognition rates compared to speech with no compensation. The levels of improvement due to RASTA processing were higher than the levels achieved due to the CMS method. Neither the CMS or RASTA methods were able to improve accuracy of the speaker recognition system for cutoff frequencies of 5 kHz, 6 kHz or 7 kHz. In the case of noisy speech all methods analysed were able to compensate for high SNR of 40 dB and 30 dB and only RASTA processing was able to compensate and improve the average recognition rate for speech corrupted with a high level of noise (SNR of 20 dB and 10 dB).
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Freedman, Alan Edward. "Transmission channel compensation in self-synchronizing chaotic systems." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36982.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaf 38).
by Alan Edward Freedman.
M.Eng.
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Haq, Khandker Nadya. "Correction and compensation of I/Q imbalance and multipath channel." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/441.
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This thesis presents adaptive schemes in overcoming signal distortion, caused by l/Q imbalance and multipath propagation, for OFDM and single carrier modulation. A combined correction and compensation scheme has been presented to mitigate the l/Q imbalance and channel for OFDM. The proposed scheme has been compared with three existing schemes. Simulations show that it successfully outperforms the other existing schemes. Similarly, for single carrier modulation two schemes have been presented for l/Q and channel mitigation.
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Jnawali, Shashwat. "RF Impairments Estimation and Compensation in Multi-Antenna OFDM Systems." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1316467659.
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Negusse, Senay. "On Parameter Estimation Employing Sinewave Fit andPhase Noise Compensation in OFDM Systems." Doctoral thesis, KTH, Signalbehandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168179.
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In today’s modern society, we are surrounded by a multitude of digital devices.The number of available digital devices is set to grow even more. As the trendcontinues, product life-cycle is a major issue in mass production of these devices.Testing and verification is responsible for a significant percentage of the productioncost of digital devices. Time efficient procedures for testing and characterization aretherefore sought for. Moreover, the need for flexible and low-cost solutions in thedesign architecture of radio frequency devices coupled with the demand for highdata rate has presented a challenge caused by interferences from the analog circuitparts. Study of digital signal processing based techniques which would alleviate theeffects of the analog impairments is therefore a pertinent subject. In the first part of this thesis, we address parameter estimation based on wave-form fitting. We look at the sinewave model for parameter estimation which iseventually used to characterize the performance of a device. The underlying goal isto formulate and analyze a set of new parameter estimators which provide a moreaccurate estimate than well known estimators. Specifically, we study the maximum-likelihood (ML) SNR estimator employing the three-parameter sine fit and derivealternative estimator based on its statistical distribution. We show that the meansquare error (MSE) of the alternative estimators is lower than the MSE of the MLestimator for a small sample size and a few of the new estimators are very close tothe Cramér-Rao lower bound (CRB). Simply put, the number of acquired measure-ment samples translate to measurement time, implying that the fewer the numberof samples required for a given accuracy, the faster the test would be. We alsostudy a sub-sampling approach for frequency estimation problem in a dual channelsinewave model with common frequency. Coprime subsampling technique is usedwhere the signals from both channels are uniformly subsampled with coprime pairof sparse samplers. Such subsampling technique is especially beneficial to lower thesampling frequency required in applications with high bandwidth requirement. TheCRB based on the co-prime subsampled data set is derived and numerical illus-trations are given showing the relation between the cost in performance based onthe mean squared error and the employed coprime factors for a given measurementtime. In the second part of the thesis, we deal with the problem of phase-noise (PHN).First, we look at a scheme in orthogonal frequency-division multiplexing (OFDM)system where pilot subcarriers are employed for joint PHN compensation, channelestimation and symbol detection. We investigate a method where the PHN statis-tics is approximated by a finite number of vectors and design a PHN codebook. Amethod of selecting the element in the codebook that is closest to the current PHNrealization with the corresponding channel estimate is discussed. We present simula-tion results showing improved performance compared to state-of-the art techniques.We also look at a sequential Monte-Carlo based method for combined channel im-pulse response and PHN tracking employing known OFDM symbols. Such techniqueallows time domain compensation of PHN such that simultaneous cancellation ofthe common phase error and reduction of the inter-carrier interference occurs.QC 20150529
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Ahmed, Sadia. "Channel Analysis and Estimation and Compensation of Doppler Shift in Underwater Acoustic Communication and Mitigation of IFI, ISI in Ultra-wideband Radio." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5408.
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Water occupies three fourth of earth's surface. The remaining one fourth is land. Although human habitats reside on land, there is no denying of the vital connection between land and water. The future sustainability of human species on this planet depends on wise utilization of all available resources, including that provided by the vast water world. Therefore, it is imperative to explore, understand, and define this massive, varying, and in many areas, unexplored water domain.
The water domain exploration and data collection can be conducted using manned or unmanned vehicles, as allowed by the water environment. This dissertation addresses three of the key difficulties that occur during underwater acoustic communication among manned and/or unmanned vehicles and proposes feasible solutions to resolve those difficulties. The focus and the contributions of this research involve the following perspectives:
1) Representation of Underwater Acoustic Communication (UAC) Channels: Providing a comprehensive classification and representation of the underwater acoustic communication channel based on the channel environment.
2) Estimation and Compensation of Doppler Shift: Providing compensation algorithm to mitigate varying Doppler shift effect over subcarriers in UAC Orthogonal Frequency Division Multiplexing (OFDM) systems.
3) Mitigation of Inter-symbol Interference (ISI): Providing feasible solution to long delay spread causing ISI in Ultra-wideband channels.
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Hubeika, Valiantsina. "Intersession Variability Compensation in Language and Speaker Identification." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235432.
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Variabilita kanálu a hovoru je velmi důležitým problémem v úloze rozpoznávání mluvčího. V současné době je ve velkém množství vědeckých článků uvedeno několik technik pro kompenzaci vlivu kanálu. Kompenzace vlivu kanálu může být implementována jak v doméně modelu, tak i v doménách příznaků i skóre. Relativně nová výkoná technika je takzvaná eigenchannel adaptace pro GMM (Gaussian Mixture Models). Mevýhodou této metody je nemožnost její aplikace na jiné klasifikátory, jako napřílad takzvané SVM (Support Vector Machines), GMM s různým počtem Gausových komponent nebo v rozpoznávání řeči s použitím skrytých markovových modelů (HMM). Řešením může být aproximace této metody, eigenchannel adaptace v doméně příznaků. Obě tyto techniky, eigenchannel adaptace v doméně modelu a doméně příznaků v systémech rozpoznávání mluvčího, jsou uvedeny v této práci. Po dosažení dobrých výsledků v rozpoznávání mluvčího, byl přínos těchto technik zkoumán pro akustický systém rozpoznávání jazyka zahrnující 14 jazyků. V této úloze má nežádoucí vliv nejen variabilita kanálu, ale i variabilita mluvčího. Výsledky jsou prezentovány na datech definovaných pro evaluaci rozpoznávání mluvčího z roku 2006 a evaluaci rozpoznávání jazyka v roce 2007, obě organizované Amerických Národním Institutem pro Standard a Technologie (NIST)
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Kurtti, S. (Sami). "Integrated receiver channel and timing discrimination circuits for a pulsed time-of-flight laser rangefinder." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526200460.
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Abstract In this thesis integrated receiver channel techniques and circuit implementations for a pulsed time-of-flight (TOF) laser rangefinder are developed with the aim to achieve centimetre level accuracy within the dynamic range of > 1:10 000 of the input pulse amplitudes. The receiver channel converts the input current pulses produced by the photo detector to voltage pulses and produces a logic-level timing pulse for the time interval measurement. In addition to the minimization of noise, the main design challenge is the minimization of the timing walk error resulting from the varying amplitude of the received optical echo. In automotive perception laser radar application, which was the target application of this work, the input amplitude of the received echo varies in a range of 1:10 000 or even more due to changes in the measured distance and reflectivity and orientation of the target. Two receiver channel and timing discriminator architectures were developed and realized as integrated circuits in 0.35 μm BiCMOS technology, and finally verified by measurements. One of the receiver channels is based on the detection of the zero-crossing of the timing pulse produced with a unipolar-to-bipolar conversion at the input of the receiver. It achieved a timing walk error of ±8 mm in a dynamic range of 1:3000. Another receiver channel is based on the leading edge timing discrimination, in which the timing walk error is being compensated for in time domain by measuring the width of the timing pulse simultaneously with its leading edge time position. An important feature of this technique, suggested in this thesis, is that it is operative also beyond the linear range of the receiver channel, which is typically limited to < 1:100. The receiver channel with leading edge detection and pulse width compensation achieved a compensated walk error of ± 2–3 mm in a dynamic range of ~ 1:100 000. The bandwidth and input referred current noise of the channel were 230 MHz and <100 nArms, respectively. The single-shot timing precision was 120 ps (20 mm in distance) at the SNR of 10. The feasibility of the receiver electronics was verified by two laser radar prototypes. An accuracy of < ± 5 mm was measured in a measurement range from 1 to 55 m, which corresponds to the receiver dynamic range of > 1:10 000 taking into consideration the varying reflectivity of the target materials usedTiivistelmä Väitöskirjatyössä on suunniteltu integroituja vastaanotintekniikoita ja –piirejä valopulssin kulkuaikamittaustekniikkaan perustuvaan laseretäisyysmittaukseen. Tavoitteena on ollut saavuttaa senttimetriluokan tarkkuus laajalla tulopulssin amplitudin dynaamisella alueella > 1:10 000. Vastaanotinkanava muuntaa valoilmaisimelta saadun tulovirtapulssin jännitepulssiksi ja muodostaa siitä logiikkatasoisen ajoituspulssin aikavälimittauspiirille. Kohinan minimoimisen lisäksi toinen suuri suunnitteluhaaste on minimoida ajoitusvirhe, jota syntyy vastaanotetun optisen tulosignaalin amplitudin vaihdellessa laajalla alueella. Työssä kehitettyjen vastaanotinkanavien yksi sovelluskohdetavoitteista on ollut autoteollisuudessa käytettävät etäisyysmittarit. Näissä tulosignaalin taso vaihtelee erittäin laajalla dynaamisella alueella, joka voi olla > 1:10 000, johtuen laajasta etäisyysmittausalueesta sekä kohteen heijastavuuden ja orientaation vaihteluista. Väitöskirjatyössä kehitettiin ja valmistettiin kaksi vastaanotin- ja ajoitusilmaisurakennetta. Piirit valmistettiin 0,35 μm BiCMOS- teknologialla, ja niiden toiminta varmistettiin mittauksilla. Ensimmäinen vastaanotinkanava-arkkitehtuuri perustuu kanavan tulossa tapahtuvaan unipolaari-bipolaari muutokseen ja sen jälkeiseen nollaylityskohdan ilmaisuun. Piirillä saavutettiin ±8 mm ajoitusvirhe 1:3000 dynaamisella alueella. Toinen vastaanotinkanava-arkkitehtuuri perustuu etureunanilmaisuun, jossa ajoitusvirhe korjataan aikatasossa mittaamalla samanaikaisesti ajoituspulssin paikka ja leveys. Ajoitusvirheenkorjausmenetelmän tärkeä ominaisuus on, että se toimii laajemmalla kuin vastaanottimen lineaarisella alueella (< 1:100). Etureunanilmaisuun ja pulssinleveyden korjaukseen perustuvalla vastaanotinkanavalla saavutettiin korjattu ajoitusvirhe ± 2–3 mm 1:100 000 dynaamisella alueella. Kanavan kaistanleveys oli 230 MHz ja tulon redusoitu virtakohina < 100 nArms. Signaalikohinasuhteella 10 laseretäisyysmittauksen kertamittaustarkkuudeksi mitattiin 120 ps (20 mm etäisyydessä). Väitöskirjatyön yhteydessä valmistettiin lisäksi kaksi prototyyppilasertutkaa, joilla varmistettiin vastaanotinelektroniikan toiminta laajalla > 1:10 000 dynaamisella tulopulssin amplitudin vaihtelualueella. Lasertutkan ajoitusvirheeksi mitattiin < ± 5 mm 1–55 m:n mittausalueella
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David, Radu Alin. "Improving Channel Estimation and Tracking Performance in Distributed MIMO Communication Systems." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/229.
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This dissertation develops and analyzes several techniques for improving channel estimation and tracking performance in distributed multi-input multi-output (D-MIMO) wireless communication systems. D-MIMO communication systems have been studied for the last decade and are known to offer the benefits of antenna arrays, e.g., improved range and data rates, to systems of single-antenna devices. D-MIMO communication systems are considered a promising technology for future wireless standards including advanced cellular communication systems. This dissertation considers problems related to channel estimation and tracking in D-MIMO communication systems and is focused on three related topics: (i) characterizing oscillator stability for nodes in D-MIMO systems, (ii) the development of an optimal unified tracking framework and a performance comparison to previously considered sub-optimal tracking approaches, and (iii) incorporating independent kinematics into dynamic channel models and using accelerometers to improve channel tracking performance. A key challenge of D-MIMO systems is estimating and tracking the time-varying channels present between each pair of nodes in the system. Even if the propagation channel between a pair of nodes is time-invariant, the independent local oscillators in each node cause the carrier phases and frequencies and the effective channels between the nodes to have random time-varying phase offsets. The first part of this dissertation considers the problem of characterizing the stability parameters of the oscillators used as references for the transmitted waveforms. Having good estimates of these parameters is critical to facilitate optimal tracking of the phase and frequency offsets. We develop a new method for estimating these oscillator stability parameters based on Allan deviation measurements and compare this method to several previously developed parameter estimation techniques based on innovation covariance whitening. The Allan deviation method is validated with both simulations and experimental data from low-precision and high-precision oscillators. The second part of this dissertation considers a D-MIMO scenario with $N_t$ transmitters and $N_r$ receivers. While there are $N_t imes N_r$ node-to-node pairwise channels in such a system, there are only $N_t + N_r$ independent oscillators. We develop a new unified tracking model where one Kalman filter jointly tracks all of the pairwise channels and compare the performance of unified tracking to previously developed suboptimal local tracking approaches where the channels are not jointly tracked. Numerical results show that unified tracking tends to provide similar beamforming performance to local tracking but can provide significantly better nullforming performance in some scenarios. The third part of this dissertation considers a scenario where the transmit nodes in a D-MIMO system have independent kinematics. In general, this makes the channel tracking problem more difficult since the independent kinematics make the D-MIMO channels less predictable. We develop dynamics models which incorporate the effects of acceleration on oscillator frequency and displacement on propagation time. The tracking performance of a system with conventional feedback is compared to a system with conventional feedback and local accelerometer measurements. Numerical results show that the tracking performance is significantly improved with local accelerometer measurements.
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Zafeiropoluos, Andreas. "An MMC-based topology with Dual-Active-Bridge power channels for load balancing in 50 Hz-railway applications." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201656.
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The purpose of this thesis report is to investigate challenges related to railway electrification. Inac-railway systems, trains are most often single-phase loads, which can create significantunbalances in the grid, when fed directly from two adjacent phases. To enhance power quality atthe railway feeding point, one alternative is to design the system such as the power is fed to thecatenary through Static Frequency Converters (SFCs), which can be a costly solution. Anotheroption is to use Static Compensators (STATCOMs) in shunt connections, handling only theunbalanced amount of power, in order to symmetrize the railway load as seen from the grid side.Modular multilevel converters (MMCs) are the state of the art solutions for medium- and highvoltage/power converter applications, such as load balancing and reactive-power compensation.This project will focus on analyzing Modular Multilevel Converter (MMC) topologies to be usedas load balancers in railway systems. However, the specific requirements of this application reveala potential weakness of MMCs. That is the asymmetrical character of the load may require muchhigher device rating in an MMC compared to a conventional converter, due to the symmetrizingcomponents to rebalance the capacitor voltages in the submodules.This project analyzes a reduced MMC-based topology with only two branches in order to meet therailway load-balancing characteristics. This chain-link compensator uses dc-dc converters tofacilitate power channels in order to restore the power imbalance, without overrating thesemiconductors in the main current path.Syftet med detta examensarbete är att studera de svårigheter som elektrifierade järnvägar står inför.När systemet utgörs av växelström kan tågen ses som en enfas last, vilket kan skapa avsevärdaobalanser i nätet då det matas från två intilliggande faser. En alternativ systemdesign för att uppnåen god effekt leverans uppnås då effekten är matad till kontaktledningen genom statiska frekvensomräknare (SFCs), detta kan dock vara en kostsam lösning. Ett annat alternativ är att användastatisk shunt kompensation (STATCOMs) som selektivt kan hantera den obalanserade effekten föratt uppnå symmetri och balans i järnvägslasten, sett från nätets sida.Modulära multiomriktare (MMCs) är en ledande teknik för omriktare till applikationer på mellanochhögspännings nivå, till exempel för lastbalans och reaktiv kompensering. Detta projektanalyserar modulära multiomriktare för lastbalansering i järnvägssystem. Kraven för dennaapplikation leder till en potentiell svaghet i MMCs där den asymmetriska karaktären på lastenkräver högre märkeffekt jämfört med konventionella omriktare. Detta på grund av de komponentersom återskapar symmetri och balans i kondensator spänningarna i submodulerna.Här analyseras en reducerad variant av MMC-baserad topologi med enbart två grenar för att mötakraven på järnvägens lastbalans. Denna kedjelänk-kompensator använder dc-dc omriktare för attstyra effektflödet till lasten vid obalanserad effekt, utan att för den skull överdimensionerahalvledarna i den ordinarie strömvägen.
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Jansson, J. P. (Jussi-Pekka). "A stabilized multi-channel CMOS time-to-digital converter based on a low frequency reference." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514299322.
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Abstract The aim of this work was to improve the performance and usability of a digital time-to-digital converter (TDC) in CMOS technology. The characteristics of the TDC were improved especially for the needs of pulsed laser time-of-flight (TOF) distance measurement, where picosecond-level precision with a long µs-level measurement range is needed in order to approach mm-level measurement accuracy. Stability in the face of process, voltage and temperature variations, multiple measurement channels, alternative measurement modes, a high integration level, standard interfaces and simple usage were the main features for development. The measurement architecture is based on counter and timing signal interpolation on two levels. The counter counts the full reference clock cycles between the timing signals, while a new recycling delay line developed in this thesis interpolates within the reference clock cycle. This technique utilizes a short delay line several times per reference clock cycle, which minimizes the interpolation nonlinearity. The same structure also makes the use of a low, MHz-level reference frequency possible, and thus only a crystal is needed as an external oscillator component. The parallel load capacitor-scaled delay line structure acts as the second, sub-gate-delay interpolation level. The INL does not accumulate in elements connected in parallel, and the load capacitance differences enable high, ps-level resolution to be achieved. Four TDC circuits in 0.35 µm CMOS technology were designed and tested in the course of this work, of which the latest, a 7-channel TDC, is able to measure the time intervals between the start pulse and three separate stop pulses in one measurement and to resolve the pulse widths or rise times at the same time. In laser TOF distance measurement this functionality can be used when several echoes arrive at the receiver, and also to compensate for the detection threshold problem known as timing walk error. The TDC achieves 8.9 ps interpolation resolution within the cycle time of a 20 MHz reference clock using only 8 delay elements on the first interpolation level and 14 delay elements on the second. A measurement precision better than 9 ps was achieved without using result post-processing or look-up tables. This work shows that versatile, high performance TDCs can be created in standard CMOS technologyTiivistelmä Väitöskirjatyön tavoitteena oli parantaa CMOS-aika-digitaalimuuntimien suorituskykyä ja käytettävyyttä. Muuntimen ominaisuuksia kehitettiin erityisesti laseretäisyysmittauksen tarpeita ajatellen, missä millimetritason mittaustarkkuus laajalla mittausaluella edellyttää aika-digitaalimuuntimelta pikosekuntitason tarkkuutta mikrosekuntien mittausalueella. Stabiilius prosessiparametri-, jännite- ja lämpötilavaihteluita vastaan, useat mittauskanavat, useat mittausmoodit, korkea integraatioaste, standardoidut liitäntäväylät ja helppo käytettävyys olivat erityisesti kehityksen kohteina. Suunniteltu mittausarkkitehtuuri koostuu laskurista ja kaksitasoisesta ajoitussignaali-interpolaattorista. Laskuri laskee kokonaiset referenssikellojaksot ajoitussignaalien välillä ja työssä kehitetty referenssiä kierrättävä viivelinjarakenne rekistereineen interpoloi ajoitussignaalien paikat referenssikellojaksojen sisältä. Referenssinkierrätystekniikka hyödyntää lyhyttä viivelinjaa useampaan kertaan kellojakson aikana, mikä minimoi epälineaarisuuden interpoloinnissa. Sama rakenne mahdollistaa myös MHz-tason referenssitaajuuden, jolloin matalataajuista kidettä voidaan käyttää referenssilähteenä. Toinen interpolointitaso koostuu rinnakkaisista kapasitanssiskaalatuista viive-elementeistä, mitkä mahdollistavat alle porttiviiveen mittausresoluution. Rinnakkaisessa rakenteessa elementtien epälineaarisuudet eivät summaudu, mikä mahdollistaa pikosekuntitason mittaustarkkuuden. Väitöskirjatyössä suunniteltiin ja toteutettiin neljä aikavälinmittauspiiriä käyttäen 0,35 µm CMOS-teknologiaa, joista viimeisin, 7-kanavainen muunnin kykenee mittaamaan aikavälin useampaan pulssiin yhdellä kertaa sekä voi selvittää samalla pulssien leveydet tai nousuajat. Laseretäisyysmittauksessa monikanavaisuutta voidaan käyttää kun useita kaikuja lähetetystä pulssista saapuu vastaanottimeen sekä kompensoimaan mittauksessa esiintyviä muita virhelähteitä. Käytettäessä 20 MHz:n kidettä referenssilähteenä muunnin saavuttaa alle 9 ps:n interpolointiresoluution ja tarkkuuden ilman epälineaarisuudenkorjaustaulukoita. Työ osoittaa, että edullisella CMOS-teknologialla voidaan toteuttaa monipuolinen ja erittäin suorituskykyinen aika-digitaalimuunnin
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Kanagasundaram, Ahilan. "Speaker verification using I-vector features." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/77834/1/Ahilan_Kanagasundaram_Thesis.pdf.
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This PhD research has provided novel solutions to three major challenges which have prevented the wide spread deployment of speaker recognition technology: (1) combating enrolment/ verification mismatch, (2) reducing the large amount of development and training data that is required and (3) reducing the duration of speech required to verify a speaker. A range of applications of speaker recognition technology from forensics in criminal investigations to secure access in banking will benefit from the research outcomes.
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Vengattaramane, Kameswaran. "Efficient Reconstruction of Two-Periodic Nonuniformly Sampled Signals Applicable to Time-Interleaved ADCs." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6253.
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Nonuniform sampling occurs in many practical applications either intentionally or unintentionally. This thesis deals with the reconstruction of two-periodic nonuniform signals which is of great importance in two-channel time-interleaved analog-to-digital converters. In a two-channel time-interleaved ADC, aperture delay mismatch between the channels gives rise to a two-periodic nonuniform sampling pattern, resulting in distortion and severely affecting the linearity of the converter. The problem is solved by digitally recovering a uniformly sampled sequence from a two-periodic nonuniformly sampled set. For this purpose, a time-varying FIR filter is employed. If the sampling pattern is known and fixed, this filter can be designed in an optimal way using least-squares or minimax design. When the sampling pattern changes now and then as during the normal operation of time-interleaved ADC, these filters have to be redesigned. This has implications on the implementation cost as general on-line design is cumbersome. To overcome this problem, a novel time-varying FIR filter with polynomial impulse response is developed and characterized in this thesis. The main advantage with these filters is that on-line design is no longer needed. It now suffices to perform only one design before implementation and in the implementation it is enough to adjust only one variable parameter when the sampling pattern changes. Thus the high implementation cost is decreased substantially.
Filter design and the associated performance metrics have been validated using MATLAB. The design space has been explored to limits imposed by machine precision on matrix inversions. Studies related to finite wordlength effects in practical filter realisations have also been carried out. These formulations can also be extended to the general M - periodic nonuniform sampling case.
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Fuelling, Meghan K. "Equity is the New Black: Examining Changes in the Executive Compensation Structures of Internet Companies." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1298.
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Executive Compensation has received a lot of media and academic attention in the last decade. Much of that attention is focused on the gross levels of compensation and not the component structure of salary, stock, options, etc. that make up a compensation package. This paper examines the executive compensation structures of internet technology firms, which are becoming an increasingly important part of the economy. I use samples of newly public and more established companies from early and recent periods to determine if and how the composition of executive pay has changed from 1997 to 2013. My findings suggest a decrease in the use of both options and salary as a percent of total compensation, with an accompanying increase in stock and overall equity percentages, has occurred between early and recent periods. Additionally, I find there to be less reliance on options and a lower mix of equity-to-salary between firms that have just gone public and more established firms, again with an increased use of stock in the component structure.
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Sansom, Andrew J., and n/a. "The role of calcium-dependent pathways in vestibular compensation." University of Otago. Department of Pharmacology & Toxicology, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070418.145158.
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Damage to one vestibular apparatus (unilateral vestibular deafferentation, UVD) results in severe postural and ocular motor disturbances (such as spontaneous nystagmus, SN) that recover over time in a process known as vestibular compensation. However, the underlying neurochemical mechanisms of vestibular compensation are poorly understood. While UVD affects many areas in the CNS, attention has focused upon the partially deafferented second order neurons in the vestibular nuclei complex (VNC). Several converging lines of evidence suggest that Ca�⁺-permeable ion channels (N-methyl-D-aspartate receptors and L-type voltage-gated Ca�⁺-channels) and intracellular Ca�⁺-dependent protein kinases play an important role in vestibular compensation. However, the nature of this involvement and the locus of these changes are unknown. The aim of this thesis was to investigate the role of Ca�⁺ signalling pathways in the VNC during vestibular compensation in guinea pig. These issues were investigated in three separate experiments that utilised two methodological approaches: i) in vitro assays were used to determine the nature and extent of protein phosphorylation within the VNC at various stages of compensation; and ii) ion channel blockers or cell-permeable kinase inhibitors were injected directly into the VNC immediately before UVD to determine whether or not these systems were causally involved in compensation.
The results of experiment 1 (Chapter 5) showed that a bolus intra-VNC injection of an uncompetitive NMDA receptor antagonist, but not an L-type voltage-gated Ca�⁺ channel antagonist, temporarily reduced SN frequency at the earliest measurement time (6 hours post-UVD). These results suggested that the initial expression of SN required, in part, the activation of NMDA receptors in the VNC on the side of the UVD, and by inference, Ca�⁺ entry through the ion channel. The results of experiment 2 (Chapter 6) revealed that the medial VNC contains abundant Ca�⁺/calmodulin-dependent and Ca�⁺/phospholipid-dependent protein kinase activities. The same VNC tissue removed from animals at various times after UVD, showed that vestibular compensation is accompanied by specific changes in the phosphorylation of several major protein kinase C substrates. These included an unidentified 46-kDa band, and a 75-kDa band with similar characteristics to the myristoylated alanine-rich C kinase substrate (MARCKS). These results suggest that protein kinase C signalling pathways may be involved in vestibular compensation. The results of experiment 3 (Chapter 7) are consistent with these results showing that intra-VNC infusion of a protein kinase C inhibitor, but not a Ca�⁺/calmodulin-dependent protein kinase II inhibitor, significantly increased SN at the earliest measurement times (6 and 8 hours), but had no effect upon the time taken to achieve compensation or on postural compensation. These results suggest that the induction of SN compensation involves protein kinase C activity in the VNC. Taken together, these findings suggest that the mechanisms underlying the expression of SN (e.g., Ca�⁺ influx via NMDA receptors) are possibly distinct from those that initiate its compensation (e.g., PKC activation). The downstream effects of raised intracellular Ca�⁺ may involve protein kinase C-dependent phosphorylation of key intracellular proteins that initiate long-lasting changes in cellular function within the VNC.
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Low, Tanner Keith. "Kinematic and Acoustic Vowel Changes in Adult Bite Block Speech." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7495.
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The current study examined the lingual kinematic and acoustic effects of bite blocks on vowels in a sentence context. Twenty adult native English speakers (10 male, 10 female) with no speech, language, or hearing deficits participated in the study. The corner vowels found in the sentence, The blue spot is on the black key again (i.e., /u/, /ɑ/, /æ/, /i/), were measured kinematically and acoustically immediately before and after bite block insertion. The participants' speech was audio-recorded and their lingual articulatory movements were measured with a Northern Digital Instruments Wave electromagnetic articulograph. The sensor coils were attached to three different parts on the tongue (back, middle, and front). Acoustic analysis of the vowel formants revealed that the vowel articulation index and vowel space area decreased significantly following bite block insertion. Kinematic analysis of the sensors on the tongue revealed that the kinematic vowel articulation index decreased significantly for the back and middle of the tongue but not for the front. Thus, adjustments to the position of the front of the tongue were sufficient to compensate for the bite block perturbation, while the same measures for the back and middle of the tongue were significantly affected. This was likely due to the relative independence in the movement of the front of the tongue, given its distance from the posterior point of attachment between the tongue and mandible. These findings suggest that the effects of articulatory perturbation can be more fully understood when kinematic and acoustic measures are considered together.
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Abisgold, J. D. "Compensation by locusts for changes in dietary nutrients : Behavioural and physiological mechanisms." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382635.
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Bales, Michael Ryan. "Illumination compensation in video surveillance analysis." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39535.
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Problems in automated video surveillance analysis caused by illumination changes are explored, and solutions are presented. Controlled experiments are first conducted to measure the responses of color targets to changes in lighting intensity and spectrum. Surfaces of dissimilar color are found to respond significantly differently. Illumination compensation model error is reduced by 70% to 80% by individually optimizing model parameters for each distinct color region, and applying a model tuned for one region to a chromatically different region increases error by a factor of 15. A background model--called BigBackground--is presented to extract large, stable, chromatically self-similar background features by identifying the dominant colors in a scene. The stability and chromatic diversity of these features make them useful reference points for quantifying illumination changes. The model is observed to cover as much as 90% of a scene, and pixels belonging to the model are 20% more stable on average than non-member pixels. Several illumination compensation techniques are developed to exploit BigBackground, and are compared with several compensation techniques from the literature. Techniques are compared in terms of foreground / background classification, and are applied to an object tracking pipeline with kinematic and appearance-based correspondence mechanisms. Compared with other techniques, BigBackground-based techniques improve foreground classification by 25% to 43%, improve tracking accuracy by an average of 20%, and better preserve object appearance for appearance-based trackers. All algorithms are implemented in C or C++ to support the consideration of runtime performance. In terms of execution speed, the BigBackground-based illumination compensation technique is measured to run on par with the simplest compensation technique used for comparison, and consistently achieves twice the frame rate of the two next-fastest techniques.
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Dah, Mustafa A. "Essays on the Effect of Excess Compensation and Governance Changes on Firm Value." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5179.
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This dissertation consists of three essays on the effect of excess compensation and corporate governance changes on the firm's performance. The first paper utilizes a cost minimization stochastic frontier approach to investigate the efficiency of director total compensation. Our findings suggest that board members are over compensated. We show that, on average, the director actual compensation level is above the efficient compensation level by around 63%. Our results suggest that an increase in director excess compensation decreases the likelihood of CEO turnover, reduces the turnover-performance sensitivity, and increases managerial entrenchment. Thus, the surplus in director compensation is directly associated with managerial job security and entrenchment. Furthermore, although director excess compensation is not significantly inversely related to the firm's future performance, it has an indirect negative effect on future performance through its impact on the entrenchment-performance relationship. Therefore, this essay proposes that the overcompensation of directors is directly associated with a board culture predicated by mutual back-scratching and collusion between the CEO and the board members. The second essay tests the effect of an exogenous shock, the Sarbanes-Oxley Act (SOX) of 2002, on the structure of corporate boards and their efficiency as a monitoring mechanism. The results suggest an increase in the participation of independent directors at the expense of insiders. Consequently, we investigate the implications of board composition changes on CEO turnover and firm value. We document a noticeable reduction in CEO turnover in the post-SOX period. We also demonstrate that, after SOX, a board dominated by independent directors is less likely to remove a CEO due to poor performance. Finally, we highlight a negative association between the change in board composition and firm value. We propose that our findings are predicated on an off equilibrium result whereby firms were forced to modify their endogenously chosen board composition. Therefore, contrary to the legislators' objectives, we suggest that the change in board structure brought about inefficient monitoring and promoted an unfavorable tradeoff between independent directors and insiders. The third essay examines the relationship between the firm's governance structure and its value during different economic conditions. We show that both relative industry turnover and CEO entrenchment increase during economic downturns. We also find that relative industry turnover and managerial entrenchment have opposite impacts on the value of the firm throughout the recessionary period. While industry turnover leads to an appreciation in firm value, managerial entrenchment reduces shareholders' wealth. The negative impact of managerial entrenchment on firm value, however, outweighs the positive impact of industry turnover. Accordingly, we propose that a recession provides managers with a good opportunity to camouflage their behavior and extract more private benefits and, thus, blame the poor performance on bad economic conditions.ID: 031001341; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed April 15, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references.
Ph.D.
Doctorate
Business Administration
Business Administration; Finance
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Nguyen, Di Kim. "X chromosome upregulation and its biological significance in mammals /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6326.
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Verdet, Florian. "Exploring variabilities through factor analysis in automatic acoustic language recognition." Phd thesis, Université d'Avignon, 2011. http://tel.archives-ouvertes.fr/tel-00954255.
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Language Recognition is the problem of discovering the language of a spoken definitionutterance. This thesis achieves this goal by using short term acoustic information within a GMM-UBM approach.The main problem of many pattern recognition applications is the variability of problemthe observed data. In the context of Language Recognition (LR), this troublesomevariability is due to the speaker characteristics, speech evolution, acquisition and transmission channels.In the context of Speaker Recognition, the variability problem is solved by solutionthe Joint Factor Analysis (JFA) technique. Here, we introduce this paradigm toLanguage Recognition. The success of JFA relies on several assumptions: The globalJFA assumption is that the observed information can be decomposed into a universalglobal part, a language-dependent part and the language-independent variabilitypart. The second, more technical assumption consists in the unwanted variability part to be thought to live in a low-dimensional, globally defined subspace. In this work, we analyze how JFA behaves in the context of a GMM-UBM LR framework. We also introduce and analyze its combination with Support Vector Machines(SVMs).The first JFA publications put all unwanted information (hence the variability) improvemen tinto one and the same component, which is thought to follow a Gaussian distribution.This handles diverse kinds of variability in a unique manner. But in practice,we observe that this hypothesis is not always verified. We have for example thecase, where the data can be divided into two clearly separate subsets, namely datafrom telephony and from broadcast sources. In this case, our detailed investigations show that there is some benefit of handling the two kinds of data with two separatesystems and then to elect the output score of the system, which corresponds to the source of the testing utterance.For selecting the score of one or the other system, we need a channel source related analyses detector. We propose here different novel designs for such automatic detectors.In this framework, we show that JFA's variability factors (of the subspace) can beused with success for detecting the source. This opens the interesting perspectiveof partitioning the data into automatically determined channel source categories,avoiding the need of source-labeled training data, which is not always available.The JFA approach results in up to 72% relative cost reduction, compared to the overall resultsGMM-UBM baseline system. Using source specific systems followed by a scoreselector, we achieve 81% relative improvement.
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Gao, Chao. "Voltage control in distribution networks using on-load tap changer transformers." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607476.
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Voltage is one of the most important parameters for electrical power networks. The Distribution Network Operators (DNOs) have the responsibility to maintain the voltage supplied to consumers within statutory limits. On-Load Tap Changer (OLTC) transformer equipped with Automatic Voltage Control (AVC) relay is the most widely used and effective voltage control device. Due to a variety of advantages of adding Distributed Generation (DG), more and more distributed resources are connected to local distribution networks to solve constraints of networks, reduce the losses from power supply station to consumers. When DG is connected, the direction of power flow can be reversed when the DG output power exceeds the local load. This means that the bidirectional power flow can either be from power grid towards loads, or vice versa. The connection point of DG may suffer overvoltage when the DG is producing a large amount of apparent power. The intermittent nature of renewable energy resources which are most frequently used in DG technology results in uncertainty of distribution network operation. Overall, conventional OLTC voltage control methods need to be changed when DG is connected to distribution networks. The required voltage control needs to address challenges outlined above and new control method need to be formulated to reduce the limitations of DG output restricted by current operational policies by DNOs. The thesis presents an analysis of voltage control using OLTC transformer with DG in distribution networks. The thesis reviews conventional OLTC voltage control schemes and existing policies of DNOs in the UK. An overview of DG technologies is also presented with their operation characteristics based on power output. The impact of DG on OLTC voltage control schemes in distribution networks is simulated and discussed. The effects of different X/R ratio of overhead line and underground cable are also considered. These impacts need to be critically assessed before any new method implementation. The thesis also introduces the new concepts of Smart Grid and Smart Meter in terms of the transition from passive to active distribution networks. The role of Smart Meter and an overview of communication technologies that could be used for voltage control are investigated. The thesis analyses the high latency of an example solution of which cost and availability are considered to demonstrate the real-time voltage control using Smart Metering with existing communication infrastructures cannot be achieved cost-effectively. The thesis provides an advanced compensation-based OLTC voltage control algorithm using Automatic Compensation Voltage Control (ACVC) technique to improve the voltage control performance with DG penetration without communication. The proposed algorithm is simulated under varying load and DG conditions based on Simulink MATLAB to show the robustness of the proposed method. A generic 11kV network in the UK is modelled to evaluate the correct control performance of the advanced voltage control algorithm while increasing the DG capacity.
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Obaid, Asfia. "Changes in the pay structures and systems in the banking sector of Pakistan : implications for a differentiated workforce and the employee psychological contract." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/changes-in-the-pay-structures-and-systems-in-the-banking-sector-of-pakistan-implications-for-a-differentiated-workforce-and-the-employee-psychological-contract(e164aa2e-bb36-4d89-849b-b65d59f29fd3).html.
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This thesis analyses the changes in pay structures and systems in the banking sector of Pakistan within a wider organisational setting of changes in multiple HR practices. It examines the outcome of these changes as perceived by different employee workgroups in the milieu of their new set of expectations. The existing literature on pay and its influence on the employee psychological contract is mostly limited to studies in the Anglo-Saxon countries. It fails to adequately highlight the ensuing conflicts of institutionalizing HRM practices which may be considered socially legitimate in western societies, in a South Asian country. While the importance of employee involvement in the design and implementation of pay practices is established in the literature there have been few studies which link the implications of its absence with employee perceptions. Moreover, the limited emphasis on the implications and consequences of applying a differentiated HR architecture within organisations fails to recognize the complex and at times conflicting relationship between different HR practices and the associated impact on multiple employee workgroups. To address these gaps in literature a qualitative case study approach was employed and interviews were conducted with 94 employees and HR managers in six domestic banks in Pakistan. The analysis reveals the policies of deregulation and privatization as the key driver for changes in the pay practice which include a partial shift from seniority to performance based pay systems, adoption of broadband pay structures and discontinuation of defined pension benefits. The other HR practices varied only slightly in design features and were applied inconsistently across the differentiated employee workgroups indicating more investment in some than others and resulting in pronounced conflicts between them. The results suggest that interrogation of outcomes of changes in bundles of HR practices, framed by an organisation’s HR architecture requires a multi-level study which incorporates the perspectives of both the employers and the employees.
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Adler, David A. "A tale of two x-linked genes : gene expression, localization and the Ohno hypothesis /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/6344.
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Patin, Alexandra [Verfasser], Bettina [Gutachter] Pause, and Rene [Gutachter] Hurlemann. "Amygdala compensation during short- and long-term changes in socialemotional and non-social-emotional contexts / Alexandra Patin ; Gutachter: Bettina Pause, Rene Hurlemann." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/113224840X/34.
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Chen, Wei. "The Impacts of Environmental Changes on Individual Behaviors in Developing Countries." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563381714920736.
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Little, VIrginia L. "Changes in Fathers' Physical Health Across the Transition to Parenthood." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1398023910.
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Sahoo, Hiranya. "4D evolution of fluvial system and channel-fill architecture of the Cretaceous Blackhawk Formation, Wasatch Plateau, Utah: An integrated fluvial rock record analysis." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1771.
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Using an integrated dataset comprising outcrop, core, GPR and LiDAR data, this study targets a high-quality outcrop "window" of the upper Cretaceous Blackhawk Formation in the eastern Wasatch Plateau in central Utah, spanning a fairly large spatial (~30 km2 area comprising eight contiguous, and vertical cliff faces) and temporal (~4 my) range. This research provides field-validation and -calibration of a wider range of fluvial heterogeneity: 1) large-scale heterogeneity (10’s of m vertically and 100’s of m laterally), 2) intermediate-scale heterogeneity (1’s of m vertically and 10’s of m laterally), and 3) small-scale heterogeneity (10’s of cm vertically and 1’s of m laterally). These sandbody- to facies-scale heterogeneities generate potential for stratigraphic compartmentalization for analogous fluvial reservoirs and prospects. Moreover, these results specifically constitute an outcrop analog to the producing tight-gas fluvial reservoirs of the adjacent hydrocarbon-prolific Uinta and Piceance Basins of Utah and Colorado, including the giant Jonah Field of Wyoming.
3D virtual outcrop model generated from LiDAR-integration has helped in avulsion-scale (~1's-10's kyr) to basin-fill scale (~100's kyr-1's myr) fluvial sandbody organization analysis down to channel-storey level. This high-resolution analysis has brought several intriguing insights. single-storey sandbodies are preferentially attendant to clustering organization, whereas multi-lateral sandbodies (i.e. channel-belt) show compensational-prone behavior. Sandbody organization is broadly compensational for the lower Blackhawk Formation, where the floodplain facies diversity is the highest. In contrast, floodplain diversity decreases stratigraphically upward such that the upper Blackhawk Formation shows the least heterogeneous floodplain with clustering-prone sandbody organization. In the quest of differentiating autogenic from allogenic signal in dynamic systems where their interplay is complexly intertwined, this study presents two incised-valley examples, where resultant fluvial organization has been interpreted, contrary to conventional wisdom, to be preferentially modulated by a dominant controlling mechanism of autogenic forcing. In filling these incised valley deposits, each of which is up to ~15-20 m thick, the dominating behavior of substrate coal compaction as an autogenic mechanism supplanted allogenic forcing (i.e. sea-level fluctuation).
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Olsson, Therese. "Miljöbedömning : Miljökonsekvensbeskrivning för prövning av muddring i Natura 2000-området Nordre älvsestuarium." Thesis, Högskolan i Halmstad, Ekologi och miljövetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-26408.
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Nordre älv är ett av två utflöden från Sveriges största vattendrag Göta älv. Estuariet som består av älvens mynning och en del av skärgården, är speciellt med blandning av sött och salt vatten och är utpekat till bland annat Natura 2000-område. I framtiden är det ett möjligt scenario att flytta delar av sjötrafiken som idag går i Göta älv genom Göteborg, till Nordre älv istället. Förutsättningarna för sjötrafiken genom Göteborg förändras i takt med att staden utvecklas och förväntade havsnivåhöjningar kan fordra större skyddsåtgärder för staden i framtiden. Här spelar både samhälls-, ekonomi- och miljöaspekter roll och en sammanvägning av konsekvenser behöver göras. Eftersom tröskelområdet i Nordre älvs mynning är mycket grunt behöver i så fall muddring utföras. Det är ett fysiskt ingrepp där bottensediment tas bort för att skapa en djupare ränna där fartyg kan passera. För ett sådant ingrepp krävs tillståndsansökan samt en miljökonsekvensbeskrivning som beskriver direkta och indirekta effekter på miljö och människa. Denna rapport är en förstudie med inspiration av miljökonsekvensbeskrivning där effekter av muddring i Nordre älvs estuarium studeras. Litteraturstudien bygger på publikationer från myndigheter och organisationer, vetenskapliga artiklar samt personlig kommunikation med berörda och sakkunniga.I estuariet finns ålgräsäng som är ett viktigt habitat för födosök och som barnkammare för många arter. Lax och öring vandrar upp genom älven för att leka och ål som är rödlistad förekommer i området. Den största effekten av muddringen är direkt borttagande av vegetation och fauna. Andra effekter som kan få stor påverkan är grumling (kortsiktigt) och förändrad hydrodynamik. Ålgräsets omfattning kommer minska men det är förhoppningsvis möjligt att genom kompensationsåtgärder öka ålgräsutbredningen utanför muddringsrännan och därigenom motverka negativ nettoeffekt. Stor tyngd bör läggas på val av tidpunkt. Under sommaren då fortplantning sker är ekosystemet mest känsligt mot störningar. Men genom god planering med åtgärder för att minska påverkan samt noga val av teknik och utrustning kan negativa miljöeffekter begränsas.För att kunna utvärdera miljöeffekterna i ett större perspektiv behöver ytterligare studier göras i och kring Göteborg för att utvärdera vilka positiva och negativa effekter som uppstår av att flytta sjöfarten och andra framtida projekt.The Nordre älv estuary is the largest of its kind in Sweden with the typical fresh and salt water mix. It contains eelgrass which is an important habitat for many organisms as feeding ground and nursery area. The estuary is protected by several different directives, laws and conventions, such as: nature reserve and Natura 2000 according to the Habitats Directive and Birds Directive issued by the EU. Because of changed conditions for marine traffic through Gothenburg it may be necessary to relocate it to the river Nordre älv in the future. That would require a dredging since the river mouth contains a shallow threshold. An environmental impact assessment (EIA) is required as part of the permit application for dredging. This essay is a literature review inspired by EIA based on publications from agencies and organizations, research, scientific articles and personal communication with experts. The major effect of dredging is directly removal of vegetation and fauna. Other effects that may have significant impact is clouding (short term) and altered hydrodynamics. Eelgrass extent will decrease but might be offset by compensational measures. Through proper planning and precautions it’s possible to reduce negative environmental impacts.
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Sathiyamoorthy, Edwin Premkumar. "GLOBAL CHANGE REACTIVE BACKGROUND SUBTRACTION." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/86.
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Background subtraction is the technique of segmenting moving foreground objects from stationary or dynamic background scenes. Background subtraction is a critical step in many computer vision applications including video surveillance, tracking, gesture recognition etc. This thesis addresses the challenges associated with the background subtraction systems due to the sudden illumination changes happening in an indoor environment. Most of the existing techniques adapt to gradual illumination changes, but fail to cope with the sudden illumination changes. Here, we introduce a Global change reactive background subtraction to model these changes as a regression function of spatial image coordinates. The regression model is learned from highly probable background regions and the background model is compensated for the illumination changes by the model parameters estimated. Experiments were performed in the indoor environment to show the effectiveness of our approach in modeling the sudden illumination changes by a higher order regression polynomial. The results of non-linear SVM regression were also presented to show the robustness of our regression model.
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Giraud, Camille. "La chance en droit administratif." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR1008.
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La chance est une notion hétérogène en droit administratif. Les manifestations de ses différentes acceptions sont en effet nombreuses tant le hasard, les probabilités et le risque auxquels la chance renvoie sont riches d’applications concrètes. Les effets de ceux-ci sont donc également, et sans surprise, très variés, de sorte que la perméabilité du droit administratif est à leur égard teintée de singularité selon qu’ils sont respectivement considérés comme bénéfiques ou néfastes. Ainsi, les probabilités sont l’illustration de ce que la chance peut être un outil utile au juge administratif dans le prononcé de ses jugements, tandis que le hasard et le risque renvoient tous deux à la survenance d’événements ou de phénomènes imprévisibles qui cherchent à être évités. Malgré toutes les subtilités déployées par la chance en droit administratif, celle-ci se révèle néanmoins comme une notion dont l’unité apparaît au stade de l’étude de sa fonction. La chance est alors une notion fonctionnelle qui a vocation à être de plus en plus employée par le juge administratif pour améliorer l’indemnisation délivrée aux administrés, tant d’un point de vue qualitatif que quantitatifChance is an heterogeneous notion in administrative law. The manifestations of its different meanings are indeed quite abundant in the sense that the coincidences, the probabilities and the risk that chance refers to are full of tangible applications. Their effects are equally, and unsurprisingly, very varied which means that the permeability of administrative law towards them is quite unique, depending on whether they are considered to be beneficial or adverse. So, probabilities illustrate how chance can be a useful tool for the administrative judge when pronouncing a judgment, whereas coincidences and risk both reflect back on the occurrence of events or unpredictable phenomenons which one would aim to avoid. Inspite of all the subtleties deployed by chance in administrative law, it nevertheless seems to be a notion, the unity of which appears to be at the study stage of its function. Chance is then a functional notion, the vocation of which is to be used more and more often by the administrative judge in order to improve the compensation awarded to citizens both from a qualitative and quantitative point of view
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Torpman, Olle. "Libertarianism and Climate Change." Doctoral thesis, Stockholms universitet, Filosofiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-128935.
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In this dissertation, I investigate the implications of libertarian morality in relation to the problem of climate change. This problem is explicated in the first chapter, where preliminary clarifications are also made. In the second chapter, I briefly explain the characteristics of libertarianism relevant to the subsequent study, including the central non-aggression principle. In chapter three, I examine whether our individual emissions of greenhouse gases, which together give rise to climate change, meet this principle. I do this based on the assumption that we are the legitimate owners of the resources we use in those activities. In the fourth chapter, I question this assumption and scrutinize libertarianism’s restrictions on appropriations of climate-relevant resources, which leads me to distinguish between some different versions of the libertarian view. Toward the end of the chapter, I also examine libertarianism’s answer to the political question regarding how emission rights should be distributed. The fifth chapter investigates libertarianism’s verdicts for mere risks of infringement, as stemming from people’s emissions and acts of appropriations. In chapter six, I investigate the libertarian right to self-defense against both the effects of climate change and other people’s climate-relevant activities. In chapter seven, I discuss two intergenerational issues related to climate change: what libertarianism says concerning future generations and how libertarianism might deal with the problem of historical emissions. The eighth chapter explores the implications of libertarianism regarding collective moral wrongdoing in connection to climate change. In chapter nine, I take a look at the libertarian room for governmental responses for tackling climate change. The tenth and final chapter is a summary. The overall conclusion of the dissertation is that libertarianism recommends that we reduce our emissions and decrease our extraction of natural resources such as forests and fossil fuels. Furthermore, governments are permitted to undertake some quite substantial actions in order to fight the causes of climate change. I end with some bottom-up reflections on what these conclusions might say about the plausibility of libertarianism. I claim that although libertarianism after all manages to explain some of our moral intuitions regarding climate change, it is questionable whether libertarianism’s explanation is better than those offered by alternative moral theories.
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Minet, Alice. "La perte de chance en droit administratif." Thesis, Paris 2, 2013. http://www.theses.fr/2013PA020004.
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Depuis plusieurs années, la perte de chance suscite l’intérêt du juge administratif et de la doctrine publiciste. Le premier, qui en a largement développé le champ dans le contentieux de la responsabilité administrative, a fait évoluer la méthode de réparation de cet instrument en s’inspirant de l’exemple judiciaire. La seconde a tenté d’identifier les justifications de l’emploi de la perte de chance en s’appuyant sur l’incertitude du préjudice et sur celle du lien de causalité. Or l’analyse de la jurisprudence montre qu’en dépit de la pluralité des aléas justifiant l’usage de la perte de chance, celui-ci s’inscrit dans un cadre unique, caractérisé par une incertitude causale. La diversité apparaît ailleurs, au stade de l’indemnisation. Selon la méthode retenue – la logique du tout ou rien ou la réparation proportionnelle – la perte de chance change d’apparence. Prenant la forme tantôt d’une présomption de causalité, tantôt d’un préjudice spécifique, elle permet de surmonter l’incertitude causale de deux manières différentes. Les hésitations actuelles du juge administratif autour de l’indemnisation de la perte de chance témoignent de la difficulté à trancher entre l’une ou l’autre des deux possibilités de réparation et, partant, entre les deux outils qui y sont attachés. Toutefois, le type d’aléa sous-tendant l’emploi du mécanisme est en mesure de fournir une clé de répartition de ces deux modalités de réparationFor several years, loss of chance has interested administrative judges and legal writing in public law. The former, who have widely developed its area in law of administrative liability, have changed the method of compensation of this instrument, by using the example of private law. The second has tried to identify the justifications of the use of loss of chance by using the uncertainty of prejudice and the one of causal relationship. But the analysis of jurisprudence shows that, despite the diversity of risks justifying the use of loss of chance, this is in keeping with a unique scope which is characterized by causal uncertainty. The variety is to be found elsewhere, at the stage of compensation. According to the selected method – the all or nothing approach or proportional compensation – the face of the loss of chance changes. It sometimes forms a presumption of causation, sometimes a prejudice, and so overcomes the causal uncertainty in two different ways. The current hesitations of administrative judges prove that it is difficult to choose between one or the other of two methods of compensation, and therefore, between the two instruments which are linked to them. However, the type of risks which underlies the use of mechanism can give a key to repartition of these two methods of compensation
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Spash, Clive L., and Clemens Gattringer. "The Economics and Ethics of Human Induced Climate Change." WU Vienna University of Economics and Business, 2016. http://epub.wu.ac.at/5073/1/sre%2Ddisc%2D2016_02.pdf.
Full textAbstract:
Human induced climate change poses a series of ethical challenges to the current political
economy, although it has often be regarded by economists as only an ethical issue for those
concerned about future generations. The central debate in economics has then concerned the
rate at which future costs and benefits should be discounted. Indeed the full range of ethical
aspects of climate change are rarely even discussed. Despite recent high profile and lengthy
academic papers on the topic the ethical remains at best superficial within climate change
economics. Recognising the necessary role of ethical judgment poses a problem for
economists who conduct exercises in cost-benefit analysis and deductive climate modelling
under the presumption of an objectivity that excludes values. Priority is frequently given to
orthodox economic methodology, but that this entails a consequentialist utilitarian philosophy
is forgotten while the terms of the debate and understanding is simultaneously restricted. We
set out to raise the relevance of a broader range of ethical issues including: intergenerational
ethics as the basis for the discount rate, interregional distribution of harm, equity and justice
issues concerning the allocation of carbon budgets, incommensurability in the context of
compensation, and the relationship of climate ethics to economic growth. We argue that the
pervasiveness of strong uncertainty in climate science, incommensurability of values and nonutilitarian
ethics are inherent features of the climate policy debate. That mainstream
economics is ill-equipped to address these issues relegates it to the category of misplaced
concreteness and its policy prescriptions are then highly misleading misrepresentations of
what constitutes ethical action. (authors' abstract)Series: SRE - Discussion Papers
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Rydholm, Allard Mattias, and Erik Insgård. "I strävan mot en grönare kommun : En kvalitativ fallstudie över Borås kommuns arbete med klimatväxling på sina enheter." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-12812.
Full textAbstract:
I detta examensarbete undersöks hur en svensk kommun kan arbeta med klimatväxling för att minska dess ekologiska fotavtryck och negativa effekt på miljön. Miljöfrågor är något som varje kommun brottas med dagligen för att föra arbetet kring hållbar utveckling framåt. Två forskningsfrågor formulerades som skulle ta reda på vilka faktorer som anställda i en svensk kommun upplever ökar miljömedvetenheten och användningen av elcykeln som arbetsfordon. Tre olika hemtjänstenheter i Borås kommun har undersökts utifrån en kvalitativ ansats ihop med en litteraturstudie. Genom att fokusera på en infrastruktur som främjar elcykelanvändandet, erbjuda utbildningar kring elcykelanvändandet samt arbeta med kampanjer som ökar tillgängligheten på elcyklar kan kommuner skapa en kulturförändring vid val av fordon. Miljöutbildningar, miljöledningssystem och elcyklar ses som fungerande sätt att klimatväxla på, med olika preferenser från person till person beroende på tidigare kunskap och erfarenheter. De tre klimatväxlingsåtgärderna upplevs på olika sätt bidra till att personer agerar på ett mer hållbart sätt. Exempelvis genom bättre resurshantering, eco-driving och via byte av fordon släpps mindre CO2 ut per resa.This thesis examines how a Swedish municipality can work with climate change to reduce its ecological footprint and negative effects on the environment. Environmental issues are something that every municipality encounters daily to forward the work on sustainable development. Two research questions were formulated that would determine the factors that employees in a Swedish municipality experience increases environmental awareness and usage of electrical bikes as work vehicles. Three different home care service units in Borås municipality has been examined based on a qualitative approach together with a literature study. By focusing on an infrastructure that encourage e-bike usage, provide education on ebikes and creating campaigns that increases the availability of e-bikes, municipalities can create a cultural change in the selection of vehicles. Environmental education, environmental management systems and e-bikes are working ways of climate compensation, with different preferences from person to person, depending on previous knowledge and experience. The three types of climate compensation alternatives are perceived as different ways to help people act more sustainable. For example, through better resource management, education in eco-driving and lesser CO2-emissions per trip by changing vehicle.
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Kvedaras, Rokas. "Automatizuotų skaitmeninių sistemų mažiems pokyčiams įvertinti tyrimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20060212_175704-20968.
Full textAbstract:
1. The method for automatic digital balancing of Wheatstone resistance bridge was developed and investigated using DAC R-2R matrix for evaluation of resistance small changes. Balancing method enables reducing of external influence impact to evaluation results and avoids most disadvantages that are common to classic systems based on unbalanced Wheatstone bridge. The parameters of connecting wires and channel switches are not impacting evaluation results in the system developed. Advantages of the system developed are proven by experiments. System developed allows low cost implementation of systems for evaluation of resistance small changes.
2. Possibilities for simplification of circuit for resistance small changes evaluation by using digital signal processing means are proven. It is established that by using known and the proposed methods for improvement of reliability of evaluation results resolution of the evaluation is 12–14 bits (0,024 % - 0,006 % accuracy). It is established that it is necessary to use digital signal processing methods for achieving such resolution.
3. New structures of resistance small change evaluation systems ensuring resolutions of 212 and 28 intended for laboratory investigations and monitoring of constructions are proposed. Experimental model of system with resolution of 28 was made and investigated. Methods of reducing noises in long cables were established during experiment. In general it was proven that the model is suitable for monitoring tasks... [to full text]
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Valdecantos, Halporn Sebastian. "Topics on open economy macroeconomics : a stock-flow consistent approach." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD034/document.
Full textAbstract:
Cette thèse présente une série d'études théoriques partageant une méthodologie commune: l'utilisation des modèles stock-flux cohérents. Sur la base de l'échec de l'outil d'analyse économique traditionnel, les modèles DSGE, je tente de montrer quels sont les principaux inconvénients de ces modèles, qui comprennent à la fois des problèmes méthodologiques et l'omission de certains aspects de la réalité qui sont cruciales (par exemple, le rôle de la monnaie et des marchés financiers). Dans le premier chapitre de cette thèse je montre pourquoi les modèles stock-flux cohérents offrent un véhicule plus précis à la compréhension des économies modernes. Ces raisons, qui sont reliés à une préoccupation plus élevé avec le réalisme, la précision comptable et l'interaction entre les différents agents économiques et des institutions sociales, expliquent pourquoi les modèles stock-flux cohérents ont réussi à détecter les instabilités qui se accumulaient dans les années avant l'éclatement de la crise financière mondiale. Après avoir expliqué la motivation pour étudier la dynamique macroéconomique par des modèles stock-flux cohérents je présente trois chapitres dans lesquels ces modèles sont adaptés à l'étude de certains problèmes spécifiques du monde réel, qui ont été et sont toujours pertinentes et ont une place privilégiée dans le agenda politique. Dans le deuxième chapitre, je étudie certaines des différentes alternatives pour la réforme du système monétaire international qui ont été proposées depuis la fin de la Seconde Guerre mondiale. A partir d'un modèle qui décrit l'état actuel des choses, il est montré comment ce modèle peut être modifié afin d'examiner comment chacun des solutions alternatives pourraient fonctionner. Ces solutions comprennent des options qui ont été largement débattues depuis des décennies, comme l'introduction du DTS (la monnaie émise par le FMI) et le bancor (la monnaie internationale que Keynes a proposé, avec la création d'une chambre de compensation internationale). Après avoir construit les modèles, des exercices de simulation sont menées. Ces expériences montrent de quelle façon chaque solution pourrait offrir un meilleur environnement mondial pour le développement des relations économiques internationales. En particulier, il est constaté que la mise en place d'une chambre de compensation comme laquelle Keynes a proposé ne serait pas seulement avantageuse à réduire les déséquilibres mondiaux, mais aussi elle pourrait produire un haut niveau de demande effective dans une échelle mondialeHis thesis presents a series of theoretical studies sharing a common methodology: the use of stock-‐flow consistent models. Based on the failure of the state of the art analytical tool of the mainstream, the so-‐called DSGE models, I attempt to show what are the main drawbacks of these models, which include both methodological problems and the omission of some aspects of reality that are crucial (e.g., the role of money and financial markets). In the first chapter of this thesis I show why stock-‐flow consistent models offer a more accurate vehicle to the understanding of modern economies. These reasons, which are connected to a higher concern with realism, accounting accuracy and the interaction between the different economic agents and social institutions, explain why stock-‐flow consistent models have been successful in detecting the instabilities that were accumulating in the years before the outbreak of the global financial crisis
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Nováček, Jaroslav. "Studium objemových změn pojivových silikátových směsí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-233785.
Full textAbstract:
In theory, this work is devoted to the principles and methods of measurement of volume changes of mortars and concretes. Emphasis is placed on cement self-levelling screeds with initial shrinkage compensation. In the practical part of the work is devoted to the development of prototype measuring system designed for non-contact detection of volume changes hydrating silicate. Using the new measurement method is also practically examined the influence of boundary conditions on hydration volume changes of selected silicate binders, cement mortar and cement levelling compound based on four different connective concepts. In the calculation, this work focuses on the numerical modelling of volume changes of the examined compounds.
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Hedberg, Agnes Holm. "Klimatneutrala byggnader : En utredning av begreppet och jämförelse mellan olika definitioner." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290800.
Full textAbstract:
Klimatförändringarna är idag ett av mänsklighetens största hot och om inte världens växthusgasutsläpp minskar drastiskt under de kommande åren kan detta medföra svåra konsekvenser både lokalt och globalt. I linje med detta har globala och nationella mål satts för att främja klimatneutrala samhällen och branscher. Byggsektorn står för en stor del av klimatpåverkan, varför det är viktigt att se över utsläpp från denna sektor. Under de senaste åren har flertalet definitioner för klimatneutralitet i byggsektorn presenterats där samtliga är överens om att detta är en viktig strategi för att minska påverkan från vår byggda miljö. Dock tycks en stor osäkerhet råda kring vad som ska inkluderas i en sådan definition. Detta projekt ämnade därför till att undersöka olika definitioner av klimatneutralitet inom byggsektorn med fokus på ‘klimatneutrala byggnader’. Sju olika verktyg inkluderas i denna analys, vilka utgör en blandning av regionala, nationella och internationella initiativ men med den gemensamma nämnaren att alla utvecklat en egen definition av en ‘klimatneutral byggnad’. En litteraturgenomgång ämnade att sätta projektet i en tydlig kontext vilket sedan följdes av en dokumentanalys av verktygen och en intervjustudie med verktygsutvecklare vilka har insyn i de olika definitionernas utformning. Resultatet visade att det råder delade meningar gällande val av systemgränser och tillvägagångssätt för att uppnå klimatneutralitet. Samtliga var överens om att förnyelsebar energiproduktion och elektrifiering kommer vara avgörande för att uppnå detta men däremot uppmärksammades olika klimatåtgärder för att balansera klimatpåverkan. Dessa inkluderade framförallt följande: produktion (och export) av förnyelsebar energi, köpt klimatkompensation och lagringsvärde av biogent kol i trämaterial. Dessutom presenterades energieffektivisering i befintligt bestånd, tekniska lösningar för att långsiktigt lagra koldioxid såsom bio-CCS, karbonatisering av betong, tillgodoräkning av en återvinningsdeklaration, återvunnet material och energi samt effektreduktion inom befintlig byggnad. Även systemgränserna skiljde sig åt där detta varierade från att framförallt inkludera det viktigaste och mest tillförlitliga till att inkludera samtliga steg inom byggnadens livscykel. Vidare visade studien på utmaningar kopplat till detta område som framförallt inkluderar brist på data, både vad gäller kvantitet och kvalitet, behovet att inludera antaganden och fiktiva beräkningar och osäkerhet kring framtiden så som elnätets mix och hantering av elektrifiering i byggsektorn. Detta indikerade att det i nuläget saknas konsensus kring vad en ‘klimatneutral byggnad’ är och att det finns utmaningar kopplat till en sådan definition, vilket tyder på att begreppet skulle behöva utvärderas ytterligare. Av den anledningen kan det vara rimligt att fundera på om klimatneutrala byggnader är ett begrepp som i nuläget är redo att användas, eller om det ska undvikas för att förhindra missförstånd.Climate change is one of today’s biggest threats for humanity and if the global greenhouse gas emissions do not drastically decrease during the near future, this could have severe consequences for the world. In line with these challenges, global and national goals have been developed which aim to foster climate-neutral societies and industries. Since the climate effect from the building industry has shown to be major, it is important to consider emissions from this sector. During the recent years, several definitions of climate-neutrality in the built environment have been presented, which is a strategy considered to be important in order to reduce the climate impact from this field. Therefore, this project aimed to investigate different definitions of climate-neutrality in the building industry with the focus ‘climate-neutral buildings’. Seven tools were included, with a mix of regional, national and international focus, which all have presented a unique definition of a climate-neutral building. To settle the project in a clear context, a literature review became the first step. Thereafter, a document analysis was conducted as well as an interview study with tool developers with good insight into the framing of the different tools that were investigated. The result showed that the definitions differ in terms of defined system boundaries and actions chosen to achieve climate-neutrality. All of the investigated tools promoted that renewable energy and electrification lay the foundation for the climate-neutral building definition. However, the climate actions presented for compensating and balancing the emissions differed. The presented actions included, above all: production (and export) of renewable energy, carbon offsets, and storage capacity of biocarbon in wood material. Additionally, the tools presented other actions which included energy-efficiency in existing buildings, technical solutions for long-term storage of carbon, carbonization of concrete, value connected to reuse of material and energy, as well as reduced energy-peak demand. The system boundaries differed in terms of inclusion of life cycle modules, from focusing on the most important and accurate stages, to include the full lifecycle of a building. Furthermore, the study identified challenges connected to the definition of climate-neutral buildings. These included, above all, lack of (high-quality) data, the need to use fictitious numbers and assumptions, as well as insecurities connected to the future, including the composition of the electricity mix and how the electricity grid will handle the electrification of the built environment. All these aspects indicate that the term climate-neutral building as for now lacks consensus and that there are challenges connected to this field. Therefore, 2 more evaluation seems to be needed and it might be reasonable to consider if climate neutral buildings as a concept is mature enough to be used, or if this should be avoided to prevent confusion and misunderstandings.
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Fadhlaoui, Hinda. "Réformes évolutionnistes du système des paiements internationaux : la création de systèmes des paiements supranationaux, une nécessité au regard des défauts du régime monétaire international actuel." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00869626.
Full textAbstract:
Au plus fort de la crise, le régime monétaire international se révèle être impuissantlorsqu'il s'agit de limiter la volatilité excessive des taux de change, l'ampleur desdéséquilibres des balances de paiements courants, le développement d'une spéculationeffrénée sur les marchés des changes et l'asymétrie entre pays en excédent et pays endéficit. Cette thèse, qui a eu le mérite d'ouvrir des pistes nouvelles dans lacompréhension des rapports complexes entre les déséquilibres mondiaux et le régimeactuel, a montré que ces déséquilibres sont intrinsèquement rattachés aux défaillances dela structure monétaire internationale. Pour interrompre cette dynamique qui détériore lesdéséquilibres mondiaux, nous proposons que le régime tende vers un système centraliséavec la création d'une monnaie internationale et d'une chambre de compensation. Cettethèse, qui réactualise le plan Keynes, inclut également des dispositions statutaires visant àajuster automatiquement les dettes extérieures aux capacités de paiement des pays. Bienque cette réforme soit une avancée, cette réflexion n'occulte pas les progrès qu'il reste àfaire pour résorber les déséquilibres extérieurs. Pour améliorer l'efficacité et la pérennitédu système des paiements internationaux, il est utile de renforcer la coopération desbanques centrales, notamment dans un contexte marqué par les crises d'endettementextérieur. Dans ce sens, cette thèse montre les opportunités qu'offre la constitution dezones monétaires régionales intégrées dans une union monétaire internationale
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Brohe, Arnaud. "Réalisations et limites des marchés du carbone: évaluation et perspectives." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209301.
Full textAbstract:
L'objectif de notre thèse vise à évaluer les résultats engrangés par les marchés du carbone. Afin de pouvoir explorer différents aspects des marchés du carbone à un niveau mondial et en raison de la diversité des instruments qui se cachent derrière ce vocable, nous avons choisi de réaliser une thèse par article. Sur base de nos analyses empiriques nous avons pu vérifier dans quelle mesure les avantages et les limites théoriques des marchés du carbone se sont réalisés en pratique. Une hypothèse forte des marchés du carbone dotés d’un système de plafonnement est qu’ils permettraient de garantir le respect des objectifs climatiques. Cette hypothèse ne s’est pas révélée exacte. En générant plus d’un milliard de crédits, dont un nombre important de crédits issus de projets, et en ne parvenant pas à empêcher des défections, le système mis en place par le Protocole de Kyoto n’est pas parvenu à garantir le plafonnement des émissions dans les pays développés. Il en va de même pour les systèmes liés à Kyoto comme le système communautaire d'échange de quotas d'émissions (SCEQE).
Dans la plupart des configurations des règles ad hoc et peu transparentes ont nui à l’objectif environnemental. La comptabilité commune de différents gaz à effet de serre, malgré des incertitudes importantes sur les pouvoirs de réchauffement globaux a également été néfaste à l'intégrité du système.
Le lien à des mécanismes de projets trouvant leur légitimité dans une preuve de l’additionnalité souvent floue demeure problématique. Notre analyse a ainsi mis en avant la problématique de l'enregistrement de projets hydrauliques dont la décision de construction est antérieure aux marchés du carbone.
En théorie, le mécanisme d’échange a pour conséquence que les acteurs confrontés à des coûts de réduction faibles soient encouragés à réduire leurs émissions. Dans la pratique, notre analyse montre que peu d’acteurs connaissent leur coût de réduction marginal, empêchant dès lors la concrétisation de cet idéal d’une réduction au moindre coût. Nous avons aussi mis en avant le fait qu’un prix identique par tonne de CO2 réduite n’est pas adapté au soutien de technologies nouvelles, souvent plus onéreuses au début de leur cycle de développement.
Finalement, un des principaux mérites des marchés du carbone a peut-être été leur acceptabilité auprès des décideurs politiques et économiques. Il est manifeste que les marchés permettent d'internaliser le carbone à un niveau international sans passer par une difficile harmonisation des politiques fiscales. C'est clairement une des raisons de leur adoption rapide et dans de nombreux pays.
Les marchés du carbone ont aussi joué un rôle important en matière de sensibilisation aux changements climatiques. Ils ont permis de faire progresser la comptabilité carbone et la compréhension des technologies sobres en carbone.
L’effondrement récent du prix du carbone montre que ce nouvel instrument qui, en théorie, est efficace pour atteindre un objectif de réduction prédéfini, ne permet pas, dans la pratique, par manque d’ambition ou en raison d’erreurs dans la conception, de financer la transition vers une nouvelle économie sobre en carbone. Il apparaît dès lors nécessaire de réformer cet instrument mais aussi de développer progressivement des alternatives afin de ne pas uniquement faire reposer la réussite de l’atteinte des objectifs climatiques sur les seuls marchés du carbone et ainsi augmenter la résilience des politiques climatiques aux aléas de marchés financiers, par ailleurs eux-mêmes soumis à de nombreux tourments depuis 2008.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Rotoullié, Jean-Charles. "L'utilisation de la technique de marché en droit de l'environnement. L'exemple du système européen d'échange des quotas d'émission de gaz à effet de serre." Thesis, Paris 2, 2015. http://www.theses.fr/2015PA020053.
Full textAbstract:
L’objectif de cette étude est d’appréhender, à travers l’exemple du système européen d’échange des quotas d’émission de gaz à effet de serre, les conditions d’efficacité d’un instrument particulier de réalisation du développement durable : la technique de marché. Définie comme un instrument de police consistant en la poursuite d’un objectif de politique publique, préalablement défini par les pouvoirs publics, au moyen de la création volontaire d’un marché, c’est-à-dire l’organisation d’échanges d’« unités » entre opérateurs économiques, la technique de marché est utilisée de manière privilégiée en matière environnementale. La création ex nihilo d’un marché pour protéger l’environnement ne doit pas induire en erreur : la technique de marché ne conduit pas à une substitution de la liberté à la puissance publique. Au contraire, la technique de marché n’est efficace que si elle est sous-tendue par une action publique forte. Une intervention permanente – au stade de l’élaboration et de la mise en oeuvre de cet instrument – et multiforme – au niveau international, régional et national – de la puissance publique est nécessaire. La « main invisible » du marché ne produit ses effets que grâce à la « main visible » de la puissance publiqueBy taking the example of the European Union emission trading system, the objective of the present study is to understand the conditions of effectiveness of a specific tool: the market-based instrument. Market-based instrument is defined as a tool of policing aiming at the achievement of a public policy objective (pre-established by public authorities) with the creation of a market, i.e. the organisation of exchanges of “units” between economic operators. This tool is widely used in environmental law. The ex nihilo creation of a market in order to protect the environment must not mislead: the market-based instrument does not lead to a shift from public action to freedom. To the contrary, the effectiveness of the market-based instrument depends on a strong public action. A permanent (i.e. both during the preparation and the implementation of this tool) and multifaceted (i.e. at international, regional and national levels) public intervention is therefore required. The “invisible hand” of the market could only be effective with the “visible hand” of public authorities
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Ming-Fung, Yuan, and 袁明豐. "Magnetic recording channel characterization, equalziation and compensation." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/73694076156959641707.
Full textAbstract:
碩士國立中央大學
資訊及電子工程研究所
82
To further increase the storage densities and reliability that systems using run-length limited (RLL) coding and peak detection (PD) can achieve, a more advanced technique on signal processing consisting of partial-response (PR) channel in combination with maximum-likelihood sequence detection (MLSD) is referred to as the PRML channel. Design a PRML system, the channel should be precisely characterized, and then the channel can be equalized and deteceed correctly. The nonlinear effects in high recording density should be compensated to improve the system performance.
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Fan, Yu-Hsiao, and 樊昱孝. "Semi-Blind SFBC OFDM Channel Estimation with an Improved Channel Compensation Scheme." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/10469844345563354612.
Full textAbstract:
碩士國立中央大學
通訊工程研究所碩士在職專班
98
Channel estimation has been a widely studied research topic in OFDM systems. In this thesis, we consider the semi-blind approach for channel tracking used in space frequency block code (SFBC) MIMO-OFDM. The advantage of the semi-blind method is little occupancy of bandwidth. The proposed algorithm can estimate the channel response by using the conventional decision feedback scheme or a modified constant modulus algorithm (CMA) based on an automatic switching mechanism in terms of the channel status. Besides, a modified channel estimation method is performed by applying the interpolation or the extrapolation scheme for channel compensation. Simulation results show that the proposed switching method in combination with the modified channel compensation scheme outperforms the method using only decision feedback or the modified CMA.
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Chang, Jui-Tien, and 張瑞典. "Channel Estimation and Compensation for the LTE Wireless System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/96662117900005793046.
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碩士國立臺灣海洋大學
通訊與導航工程學系
99
Long Term Evolution (LTE) system is a possible candidate for the next generation wireless communications. It supports up to 20MHz maximum bandwidth. Due to the wideband transmission, the transmitted signals will suffer from time-varying and frequency-selective fading channel that degrade the system performance dramatically. Therefore, it is an important issue of the channel estimation and compensation for a wireless system. In this thesis, we compared the performance of different channel estimation methods under the LTE specifications. Besides, we proposed the Zero-Padding channel estimation method with iterative IBI cancellation to mitigate the Inter Block Interference (IBI) effect resulted from the added Cyclic Prefix (CP) is shorten than the Channel Impulse Response (CIR). Moreover, it is well-known that the Linear-Interpolated channel estimation method has the simple and easy implementation advantages. The thesis also tried to find its suitable scenarios. Finally, some measured channel responses are conducted to verify the performance of different channel estimation methods in this thesis.
46
林政賢. "A reliablity-guided channel and bandwidth mismatch compensation for robust speech recognition." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/34158147911976481602.
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Liu, Der-Zhenh, and 柳德政. "Synchronization and Channel Compensation Techniques for Digital Mobile and Personal Communication Systems." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/36082935565445620973.
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博士國立交通大學
電子工程系
89
For future mobile and personal communication systems, high data-rate transmission is the most important requirement. In order to employ the multilevel differential modulation transmission in the burst mode high data-rate digital mobile and personal communication systems, several new techniques, including symbol timing synchronization, frequency offset compensation, channel compensation and frame synchronization, are proposed and investigated in this thesis. Since the design of the receiver depends on the modulation method in the transmitter and channel characteristics in the wireless environments, this thesis is separated to four parts. In the first part, we present a synchronization scheme, combining symbol timing recovery and frequency offset compensation, associated with the differential detection for MDPSK signals. The characteristic (average output versus timing error) of Gardner''s timing error detector after differential phase detector has been proved having an S-curve shape. It is not only independent of the modulation level of DPSK signals, but also the residual phase error and frequency offset in demodulated signals. The frequency offset compensation can increase the tolerance of frequency offset in data detection, and reduce the degradation of BER performance caused by frequency offset. Computer simulation results show that the proposed synchronization scheme has good performance for MDPSK signals in the AWGN channel and frequency-nonselective fading channel even with frequency offset and residual phase error. In the second part, we propose a novel channel estimation and compensation technique for the preamble-assisted DAPSK transmission. The received preamble signals are used to estimate the combined distortions due to multipath fading and frequency offset. The detected data symbols as well as preamble symbols are used to enhance the accuracy of estimation process. The combined distortions can be corrected in the data symbol at the same time. The storage-delay time of the estimation process is only several symbols long. A series of computer simulations have been carried out to investigate the BER performances of the preamble-assisted 16DAPSK signals with uncertain frequency offset in the frequency-nonselective and frequency-selective fading channels. In the third part, we present a symbol timing recovery scheme employing adaptive interpolation filter. The unknown timing error of the sampling clock generated by fixed a free-running local oscillator can be estimated from the received samples by the timing error estimation. The received samples are first processed by a square-law nonlinear operation. Then, the timing error can be extracted directly by the phase of the first Fourier coefficient at symbol rate. For symbol detection, the received samples are first delayed by a programmable delay block, which is controlled by the timing error estimate. And then, the adaptive interpolation filter is adopted to mitigate both the unknown residual timing error and intersymbol interference due to multipath fading simultaneously. The tap-weights of the adaptive interpolation filter are updated both by the timing error estimate and the error signal. Computer simulations show that the proposed adaptive interpolation filter scheme outperforms the other conventional schemes in the wireless environments with multipath fading, frequency offset, and phase error. Since the aforementioned synchronization and channel compensation techniques require some preamble signals, a frame synchronization scheme is necessary at the receiver. In the fourth part, we present a simple frame synchronization scheme using fractionally-spaced sequence-matched correlators without exact symbol synchronization. At the same time, a low-complexity frame synchronization scheme using a single bit-sequence-matched correlator is also presented to reduce the hardware complexity. A series of computer simulations have been carried out to evaluate the performance of the proposed frame synchronization scheme with a suitable threshold parameter for the preamble-assisted DAPSK transmission in the wireless environments.
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Li, Yun-Yu, and 李昀祐. "Blind Receiver with Channel Shortening/Equalization and CFO Compensation for 5G Communication." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/72026222007186687621.
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碩士國立中興大學
電機工程學系所
104
In the Fifth Generation(5G) communication system ,the research about it can be sorted higher data rates ,massive number of devices and low-latency high-reliability ,etc. The Short-Packet Communications (SPC) is a concerned application in the subject about low-latency high-reliability. Due to the property of SPC, efficiently reducing the length of cyclic prefix (CP) and length of pilot is a important study. This paper proposes a blind receiver for SPC system that do not need to joint pilot and can solve the interblock interference (IBI) caused by CP length not enough. The proposed receiver exhibits a four-stage structure: the first stage performs blind shortening of channel impulse responses (CIRs),without needing neither a priori knowledge of the CIRs to be shortened, nor preliminary compensation of the CFOs; the second stage performs joint estimation and compensation of the CFOs; the third stage implements signal-to-noise ratio (SNR) maximization, without requiring knowledge of the shortened CIRs; the fourth stage performs blind adaptive equalization with fractional lower-order constant modulus algorithm(FLOS _CMA) algorithm to update the equalization.
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Yeh, Shao-Ying, and 葉邵穎. "Compensation for Deep Fading Effect of Two-Ray Channel in OFDM System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/96681554167438053423.
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碩士國立交通大學
資訊科學與工程研究所
97
This paper proposes a method in Rx for deep-fading channel with no variation Tx. Because of OFDM system is multicarrier modulation. Therefore, the performance is affected by selective fading. When the transmitted signal through pass the deep fading channel. The deep fading data will lose after FFT. This paper of contribution is resolved the deep-fading channel in Rx with no variation Tx. The performance is convergent on 36dB with the data rate 3/4 and 64QAM.
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Jhang, Yi-Wei, and 張益瑋. "Adaptive Channel estimation/equalization and CFO compensation receiver for MIMO OFDM communication systems." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89787310512472289730.
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碩士國立中興大學
通訊工程研究所
103
In the thesis, to efficient inter-carrier interference (ICI) cancellation in Space Time Block Code (STBC) and Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM), we use an adaptive receiver and combined to construct the whole system using two-path conjugate transmission. This receiver design is based on the phase rotated conjugate cancellation (PRCC) concept presented, and we can referred as an adaptive receiver of modified the PRCC scheme. Additionally, Channel estimation has the key effect to the system performance of MIMO-OFDM. We use a Kalman filter to trace the channel .The initial channel estimate is performed from sparse pilot signals. The cycle of data detection, decoding, and channel estimation is repeated until convergence. We also derive the optimal phase rotations using the criterion of maximizing the carrier-to-interference ratio, and then develop an adaptive normalized block least mean-squared algorithm to approach the optimal solutions. With such adaptive phase rotations in the receiver, the carrier frequency offset (CFO) variations due to the channel effect and the mismatch between oscillators at the transmitter and receiver can effectively be tracked without feeding back the CFO estimate to the transmitter as required in PRCC. Simulation results demonstrate that an adaptive receiver of modified the PRCC scheme approach has better bit error rate performance than the PRCC, the conventional CC and two-stage IQ imbalance schemes for various time-varying channels.