In this thesis, two ultrasonic timing methods are used in order to investigate the accuracy and reliability of measurements for surface breaking cracks having different orientations and heights. Also the best applicable measurement technique is searched by comparing the received test results. These methods are the Time of Flight Diffraction (TOFD) Method using diffraction of longitudinal waves and another method using the reflection of shear waves from the crack tips. In order to simulate and measure the height of surface breaking cracks three sets of test blocks from steel, and two sets of wedges from plexiglas material are manufactured. Also several probes having frequencies of 2Mhz, 4Mhz, 5Mhz and angles of 45o and 70o are used. Some test procedures are created to make realistic comparisons between the test results and the ones found by previous studies in literature. The results are compared according to the standard deviations of errors in crack height measurements and it is found that the depth, orientation of defects and the frequency of probes have considerable affect on the results. With wider probe angles and higher frequencies of probes to some extent the errors are observed to be running low and the height of cracks could be measured closer to the original size. The amount of the errors is increased in measurements with the increasing angle of cracks. The results of both methods are found to be very satisfactory. A range of &plusmn / 0.5 mm for means of error from the original vertical crack heights is determined. The results agree with the previous studies.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Generations X and Y have been described as constituting a ‘black hole’ in congregational life. The literature emphasises that generations X and Y are interested in spirituality but not institutional religion. There is now a substantial body of literature arguing that generations X and Y find churches ‘irrelevant’, ‘absent of God’, ‘too rigid’, and ‘laughably out of touch’ with their lives. This thesis argues that generational accounts of religion often fail to make an important distinction between the churched and unchurched in relation to generational distinctiveness. This is a distinction often drawn by sociologists of religion, pointing to two quite different cultures, one communally orientated towards faith communities and the other orientated towards personal freedom and a privatised spiritual quest. Generations X and Y in this thesis refer to a generational unit who share a particular type of faith: owned and embedded within a church community. Employing a methodological approach of in-depth religious life story interviews this thesis is a sociological investigation into the way Christian faith journeys of GenX and GenY are embedded within New Zealand church communities. It is argued that their faith does not make sense outside of this embeddedness. Embedded faith provides a framework for making sense of the participants’ religious biographies. Embedded faith is contrasted to a more privatised understanding of faith and religion popular within sociology of religion. The active dimension of embedded faith is demonstrated through an exploration of modes of engagement with worship and preaching. This thesis builds upon qualitative studies that continue to demonstrate the salience of the collective act of religious involvement and social belonging. One of the challenges of embedded faith however, is finding a church to embed it within. This thesis provides understanding and insight into the relationship between embedded faith and church switching. It explores the way that church switching is an intentional act of disembedding and re-embedding faith and the reasons for this practice.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Generations X and Y have been described as constituting a ‘black hole’ in congregational life. The literature emphasises that generations X and Y are interested in spirituality but not institutional religion. There is now a substantial body of literature arguing that generations X and Y find churches ‘irrelevant’, ‘absent of God’, ‘too rigid’, and ‘laughably out of touch’ with their lives. This thesis argues that generational accounts of religion often fail to make an important distinction between the churched and unchurched in relation to generational distinctiveness. This is a distinction often drawn by sociologists of religion, pointing to two quite different cultures, one communally orientated towards faith communities and the other orientated towards personal freedom and a privatised spiritual quest. Generations X and Y in this thesis refer to a generational unit who share a particular type of faith: owned and embedded within a church community. Employing a methodological approach of in-depth religious life story interviews this thesis is a sociological investigation into the way Christian faith journeys of GenX and GenY are embedded within New Zealand church communities. It is argued that their faith does not make sense outside of this embeddedness. Embedded faith provides a framework for making sense of the participants’ religious biographies. Embedded faith is contrasted to a more privatised understanding of faith and religion popular within sociology of religion. The active dimension of embedded faith is demonstrated through an exploration of modes of engagement with worship and preaching. This thesis builds upon qualitative studies that continue to demonstrate the salience of the collective act of religious involvement and social belonging. One of the challenges of embedded faith however, is finding a church to embed it within. This thesis provides understanding and insight into the relationship between embedded faith and church switching. It explores the way that church switching is an intentional act of disembedding and re-embedding faith and the reasons for this practice.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Generations X and Y have been described as constituting a ‘black hole’ in congregational life. The literature emphasises that generations X and Y are interested in spirituality but not institutional religion. There is now a substantial body of literature arguing that generations X and Y find churches ‘irrelevant’, ‘absent of God’, ‘too rigid’, and ‘laughably out of touch’ with their lives. This thesis argues that generational accounts of religion often fail to make an important distinction between the churched and unchurched in relation to generational distinctiveness. This is a distinction often drawn by sociologists of religion, pointing to two quite different cultures, one communally orientated towards faith communities and the other orientated towards personal freedom and a privatised spiritual quest. Generations X and Y in this thesis refer to a generational unit who share a particular type of faith: owned and embedded within a church community. Employing a methodological approach of in-depth religious life story interviews this thesis is a sociological investigation into the way Christian faith journeys of GenX and GenY are embedded within New Zealand church communities. It is argued that their faith does not make sense outside of this embeddedness. Embedded faith provides a framework for making sense of the participants’ religious biographies. Embedded faith is contrasted to a more privatised understanding of faith and religion popular within sociology of religion. The active dimension of embedded faith is demonstrated through an exploration of modes of engagement with worship and preaching. This thesis builds upon qualitative studies that continue to demonstrate the salience of the collective act of religious involvement and social belonging. One of the challenges of embedded faith however, is finding a church to embed it within. This thesis provides understanding and insight into the relationship between embedded faith and church switching. It explores the way that church switching is an intentional act of disembedding and re-embedding faith and the reasons for this practice.

Orthogonal frequency-division multiplexing (OFDM) has been adopted by many broadband wireless communication systems for the simplicity of the receiver technique to support high data rates and user mobility. However, studies also show that the advantage of OFDM over the single-carrier modulation schemes could be substantially compromised by timing or frequency estimation errors at the receiver. In this thesis we investigate the synchronization problem for practical OFDM systems using a system model generalized from the IEEE 802.11 and IEEE 802.16 standards. For preamble based synchronization schemes, which are most common in the downlink of wireless communication systems, we propose a novel timing acquisition algorithm which minimizes false alarm probability and indirectly improves correct detection probability. We then introduce a universal fractional carrier frequency offset (CFO) estimator that outperforms conventional methods at low signal to noise ratio with lower complexity. More accurate timing and frequency estimates can be obtained by our proposed frequency-domain algorithms incorporating channel knowledge. We derive four joint frequency, timing, and channel estimators with different approximations, and then propose a hybrid integer CFO estimation scheme to provide flexible performance and complexity tradeoffs. When the exact channel delay profile is unknown at the receiver, we present a successive timing estimation algorithm to solve the timing ambiguity. Both analytical and simulation results are presented to confirm the performance of the proposed methods in various realistic channel conditions. The ranging based synchronization scheme is most commonly used in the uplink of wireless communication systems. Here we propose a successive multiuser detection algorithm to mitigate multiple access interference and achieve better performance than that of conventional single-user based methods. A reduced-complexity version of the successive algorithm feasible for hardware real-time implementation is also presented in the thesis. To better understand the performance of a ranging detector from a system point of view, we develop a technique that can directly translate a detector�s missed detection probability into the maximum number of users that the method can support in one cell with a given number of ranging opportunities. The analytical results match the simulations reasonably well and show that the proposed successive algorithms allow a base station to serve more than double the number of users supported by the conventional methods. Finally, we investigate inter-carrier interference which is caused by the timevarying communication channels. We derive the bounds on the power of residual inter-carrier interference that cannot be mitigated by a frequency-domain equalizer with a given number of taps. We also propose a Turbo equalization scheme using the novel grouped Particle filter, which approaches the performance of the Maximum A Posterior algorithm with much lower complexity.

Thesis (M.App.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 93-95). Also available in electronic format on the Internet.

Η παρούσα διπλωματική εργασία αφορά στην πειραματική αξιολόγηση του μηχανισμού ανάκτησης ρυθμού συμβόλου για ψηφιακούς δέκτες τεχνολογίας SDR που λαμβάνουν δεδομένα μέσω δορυφόρου. Η ορολογία SDR/SR (Software Defined Radio/Software Radio) χρησιμοποιείται για να χαρακτηρίσει τους πομποδέκτες που μπορούν να καθορίζουν σημαντικές παραμέτρους τους και βασικές αρχές της λειτουργίας τους μέσω αναβάθμισης ή ενημέρωσης του λογισμικού τους. Ο μηχανισμός ανάκτησης του ρυθμού συμβόλου (Symbol Timing Recovery, STR) αναπτύχθηκε στα πλαίσια της διδακτορικής διατριβής του διδάκτορος Παναγιώτη Σαββόπουλου. Η παρούσα εργασία μελετά τη σύγκλιση του βρόχου υπό συνθήκες παραμένοντος σφάλματος συχνότητας καθώς επίσης και τον προσδιορισμό του λόγου σήματος προς θόρυβο στην έξοδο του βρόχου κάνοντας χρήση ενός νέου μεγέθους, metric, το οποίο έχει εισαχθεί στα πλαίσια της προαναφερθείσας διδακτορικής διατριβής, υπό συνθήκες λευκού Gaussian θορύβου. Το μέγεθος αυτό είναι σε θέση να δώσει αξιόπιστα αποτελέσματα στις ενδιάμεσες υπομονάδες του δέκτη υπό συνθήκες παραμένοντος σφάλματος συχνότητας. Στην παρούσα εργασία μελετώνται οι QPSK, 8PSK, 16-APSK και 32-APSK διαμορφώσεις διότι αυτές οι διαμορφώσεις χρησιμοποιούνται από το πρότυπο DVB-S2. / The purpose of this project is the experimental evaluation of a mechanism for the symbol timing recovery which is used in digital Software Defined Radio receivers. SDR/SR (Software Defined Radio/Software Radio) technology is used to characterise the transmitters and the receivers which are able to determine important parameters and basic primciples for their function through upgrade or briefing of their software. The symbol timing recovery mechanism (STR) was developped in terms of the doctora of dr Panagiotis Savopoylos. The precent project examines the loop’s convergence when there is frequency error as well as the signal to noise ratio in the output of STR with the use of a new size, metric, which was also developped in terms of the doctora which was mentioned before, when there is white Gaussian noise. The metric is able to give reliable results in the intermediate stages of the receiver when there is frequency error. In the precent project are examined the QPSK, 8PSK,16-APSK, 32-APSK modulations because these modulations are used in DVB-S2 standard.

Previous research has shown that orienting attention in time can help to improve behavioural outcomes. However, the extent to which temporal orienting can be preserved in ageing and in the context of neurological disorders remains unresolved. This thesis therefore explores temporal expectations in the healthy ageing and diseased brain by taking a neuropsychological approach. To begin, I provide an overview of the literature in <b>Chapter 1</b> most relevant for the following investigation. Four chapters of experiments then follow. To examine the effects of ageing on temporal expectation, the performance of healthy young adults and healthy older adults is presented and the results are discussed in <b>Chapter 2</b> and <b>3</b>. Though it had been previously shown that older adults seem to experience an expectation deficit on temporal expectation tasks, these chapters demonstrate the preservation of temporal expectation in ageing. On their own, these findings represent an important and novel contribution to the literature; however, this research is incapable of establishing the causal mechanisms involved in temporal expectation. To explore the causal role of relevant brain regions in temporal expectation, <b>Chapter 4</b> and <b>5</b> investigate the effects of temporal orienting in participants with damage to the basal ganglia - a brain region strongly implicated in temporal processing. In <b>Chapter 4</b>, the role of the basal ganglia in temporal expectations is examined using data collected from participants with Parkinson's disease and contrasts their performance with age-matched healthy controls. To complement this investigation, and to provide converging evidence for the basal ganglia's role in temporal expectations, Chapter 5 investigates the behavioural performance of individuals with focal lesions to the basal ganglia. The findings in this thesis are discussed in their wider context in Chapter 6, and directions for future research are proposed.

Actuellement, les techniques multiporteuses sont largement utilisées dans les systèmes de transmission grâce à leur robustesse aux effets de trajets multiples et à leur implémentation efficace utilisant des FFTs. L'OFDM (orthogonal frequency division multiplexing) est un type de modulation multiporteuse qui consiste à subdiviser un flux de données à très haut débit en plusieurs flux élémentaires à bas-débit qui sont transmis sur différentes sous-porteuses orthogonales. Récemment, une technique multiporteuse à base de bancs de filtres (FBMC) a été proposée comme une alternative permettant d'offrir quelques avantages par rapport à l'OFDM. Un des principaux avantages est l'amélioration de l'efficacité spectrale grâce à l'absence du préfixe cyclique (CP) et aux formes d'onde bien localisées en temps et en fréquence.Contrairement à ce qui est souvent supposé dans la littérature, l'asynchronisme existe intrinsèquement dans un bon nombre de systèmes de communication à cause de multiples facteurs tels que les délais de propagation et la distribution géographique des utilisateurs. Cet asynchronisme peut engendrer une perte d'orthogonalité entre les sous-porteuses qui peut se traduire par l'apparition d'interférences asynchrones causant à leurs tours une dégradation des performances du système. La modélisation de cette interférence présente un enjeu important dans la conception des systèmes de communication.Dans cette thèse, nous analysons l'impact de la désynchronisation temporelle sur les performances de l'OFDM et de la FBMC. Tout d'abord, nous présentons un modèle global permettant la caractérisation et l'analyse de l'interférence dans les systèmes multiporteuses asynchrones. Une nouvelle famille de tables d'interférence est proposée tenant compte du décalage temporel ainsi que de la distance spectrale entre les sous-porteuses interférente et victime. Les termes de ces tables sont calculés pour CP-OFDM et FBMC avec les deux formes d'onde IOTA et PHYDYAS. L'impact de l'interférence asynchrone sur le taux d'erreur (BER) et sur l'efficacité spectrale de l'OFDM/FBMC est examiné. En se basant sur les fonctions génératrices des moments de la puissance d'interférence, nous avons établi des expressions analytiques simples du BER et de l'efficacité spectrale moyens. Ces dernières expressions réduisent d'une façon considérable la complexité de l'évaluation des performances. Cette étude théorique a été consolidée et validée par des résultats de simulation pour différents scénarios où nous avons démontré que contrairement à l'OFDM, les modulations FBMC sont moins sensible à la désynchronisation temporelle grâce à la bonne localisation des formes d'ondes utilisées. / Multicarrier systems are widely used today due to their robustness to multipath effects and efficient implementation using FFT. Orthogonal Frequency Division Multiplexing (OFDM) system is a class of multicarrier modulation which consists of splitting up a wide-band signal at a high symbol rate into several lower rate signals, each one occupying a narrower band. System performance improves because subcarriers experience flat fading channels and are orthogonal to one another. Recently, a number of papers have focused on a new alternative called Filter bank based multicarrier system (FBMC) which can offer a number of advantages over CP-OFDM system such as the improved spectral efficiency by not using a redundant CP and by having much better control of the out-of-band emission due to the time-frequency localized shaping pulses.Furthermore, asynchronism inherently exists in several communication systems due to many factors e.g. the propagation delays and the spatial distribution of users. As one of the most challenging issue in design of communication systems, the asynchronism can harmfully affect the system performance by causing the so-called asynchronous interference.In this dissertation, we investigate the impact of asynchronism on the performance of OFDM FBMC systems. First, we present a unified framework for multicarrier interference characterization and analysis in asynchronous environments. We propose a new family of interference tables that model the correlation between a given interfering subcarrier and the victim one, not only as a function of the spectral distance separating both subcarriers but also with respect to the timing misalignment between the subcarriers holders. These tables are derived for CP-OFDM, PHYDYAS-FBMC and IOTA-FBMC systems. Furthermore, the impact of the asynchronous interference on the average error rate and the average spectral efficiency of OFDM and FBMC systems is addressed. Based on computing the moment generating functions of the asynchronous interference power, simple new expressions for the exact evaluation of the average error rate and the average spectral efficiency are derived considering the frequency correlation fading between adjacent interfering subcarriers. These expressions significantly reduce the computation complexity of the performance evaluation.For each technique two scenarios are examined: fully-loaded network and partially loaded ones. The accuracy of the obtained expressions has been validated through different simulation results. In contrast to OFDM, FBMC waveforms are demonstrated to be less sensitive to timing asynchronism, due to the better frequency localization of the used prototype filters.

Abstract The laws and financial structure of a country can affect firm decisions and outcomes by affecting financial constraints and agency problems. Power theories of credit suggest that the legal rights of creditors, such as the ability to grab collateral in bankruptcy, increase the willingness of lenders to extend credit. Shareholder protection can reduce information asymmetry and agency problems by mandating quality disclosures, stipulating approval procedures for potentially conflicted transactions and facilitating the private litigation process. The bank-based financial structure can reduce moral hazard by alleviating the free-rider problem in monitoring. This dissertation contains various novel results. The first essay presents evidence of an inverse relation between creditor rights and the value of cash. This is consistent with financial constraints increasing the marginal value of cash, and creditor rights alleviating financial constraints. The second essay suggests that the bank-based financial structure improves the operating performance of large investments especially for diffusely held firms, consistent with the less prevalent free-rider problem in monitoring. The third essay shows that shareholder protection raises investment hazard for the smallest firms. This is consistent with the notion that shareholder protection alleviates those asymmetric information-related problems that delay investment, such as cash flow diversion by corporate insiders. In addition to contributing to the scientific literature, the results of this dissertation can have practical implications for companies, suppliers of finance and policymakers. A value-maximizing company should take into account its legal environment when deciding on cash holdings. Suppliers of finance should consider the interplay between financial structure and ownership structure when evaluating the profitability of investments. Policymakers often encourage investments due to their effect on employment and tax income. The results of this dissertation show that investor protection increases the frequency of large investments and their profitability. / Tiivistelmä Maan lait ja rahoitusrakenne voivat vaikuttaa yrityksen päätöksentekoon rahoitusrajoitteiden ja agenttiongelmien kautta. Velkojien vaikutusvaltaan perustuvien teorioiden mukaan velkojan oikeudet, kuten oikeus vakuuteen konkurssin yhteydessä, lisäävät velanantajan lainaamishalukkuutta. Osakkeenomistajia suojaavat lait voivat puolestaan vähentää yrityksen ja sijoittajien välistä epäsymmetristä informaatiota ja agenttiongelmia esimerkiksi vaatimalla laadukkaita ilmoituksia ja hyväksymisprosesseja koskien potentiaalisesti eturistiriitoja sisältäviä transaktioita sekä mahdollistamalla yksityisen kanteen nostamisen. Lisäksi maan pankkiperusteinen rahoitusrakenne voi vähentää moraalikatoa lievittämällä vapaamatkustajaongelmaa yritysjohdon monitoroinnissa. Tämä tutkielma sisältää useita uusia tuloksia. Ensimmäisessä esseessä havaitaan käänteinen yhteys velkojien oikeuksien ja kassan arvon välillä. Johdonmukainen selitys tälle havainnolle on, että rahoitusrajoitteet lisäävät kassan marginaaliarvoa ja velkojien oikeudet lieventävät rahoitusrajoitteita. Toisen esseen tulosten mukaan pankkiperusteinen rahoitusrakenne parantaa suurten investointien vaikutusta operatiiviseen tulokseen eritysesti hajaantuneen omistusrakenteen omaavien yritysten osalta. Tämä voi johtua pankkiperusteisen rahoitusjärjestelmän vapaamatkustajaongelmaa vähentävästä vaikutuksesta. Kolmannen esseen tulosten mukaan osakkeenomistajansuoja kohottaa suurten investointien hasardifunktiota pienimpien yritysten osalta. Tämä puolestaan voi johtua siitä, että osakkeenomistajansuoja lievittää investointeja hidastavia epäsymmetrisen informaation ongelmia, kuten yrityksen sisäpiiriläisten mahdollista taipumusta ohjata yrityksen kassavirtoja heitä itseään hyödyttäviin kohteisiin. Tieteellisen kontribuution lisäksi tutkimustuloksia voidaan hyödyntää yritysten, rahoittajien ja politiikkojen päätöksenteossa. Yrityksen arvoa maksimoivan johtajan tulisi kassan suuruutta päättäessään ottaa huomioon maassa vallitseva lakiympäristö. Rahoittajien tulisi puolestaan huomioida maan rahoitusrakenteen ja yrityksen omistusrakenteen vaikutus investointien kannattavuuteen. Politiikkojen yleinen tavoite on lisätä yritysten investointeja, koska ne parantavat työllisyyttä ja synnyttävät verotuloja. Tämän tutkielman mukaan sijoittajansuoja lisää suurten investointien frekvenssiä ja kannattavuutta.