Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation between surface and bulk effects. By using an angular interrogation, both surface plasmons are simultaneously excited at the same location and wavelength but at different angles. Angular interrogation offers at least a factor of 3.6 improvement in surface and bulk cross-sensitivity compared to wavelength-interrogated dual-mode SPR sensors. Multi-mode SPR sensors supporting at least three surface-plasmon modes can differentiate a target surface effect from interfering surface effects and bulk index changes. This dissertation describes a tri-mode SPR sensor which supports three surface plasmon resonance modes at one single sensing position, where each mode is excited at a different wavelength. The tri-mode SPR sensor can successfully differentiate specific binding from the non-specific binding and bulk index changes.

This Ph.D. thesis represents a summative report detailing research processes and outcomes from investigating the ultimate and serviceability limit state short- and long-term behaviour and design of timber-concrete composite floors. The project enables the realization of a semi-prefabricated LVL-concrete composite floor system of up to 15 m long using 3 types of connection. Design span tables which satisfy the ultimate and serviceability limit state short- and long-term verifications for this system form the novel contribution of this thesis. In quantifying the behaviour of timber-concrete composite floors, 5 different experimental phases have been carried. 9 major achievements in meeting 9 sub-objectives have been concluded: 1) Three best types of connection system for timber-concrete composite floors have been identified; 2) The characteristic strength and secant slip moduli for these connections have been determined; 3) The short-term behaviour of the selected connections defined by their pre- and post-peak responses under collapse load has been established; 4) An analytical model for the strength evaluation of the selected connections based on the different possible modes of failure has been derived; 5) Easy and fast erected semi-prefabricated timber-concrete composite floor has been proposed; 6) The short-term ultimate and serviceability limit state behaviour of timber-concrete composite floor beams under collapse load has been investigated; 7) The long-term behaviour of chosen connections defined by their creep coefficient has been determined; 8) The long-term behaviour of timber-concrete composite floor beams under sustained load at serviceability limit state condition has been investigated; and 9) Design example and span tables for semi-prefabricated timber-concrete composite floors that satisfy both the ultimate and serviceability limit state in the short- and long-term using the gamma-method have been developed.

Fluorescence spectroscopy was examined as a potential technique for identifying aerosol particles like bacterial spores. This technique was used for laboratory measurements on some common biological agent simulants. We have measured the intrinsic steady-state fluorescence emission spectra as a function of the excitation wavelength for several bacterial spores (washed and unwashed) in dry and aqueous suspensions at room temperature using excitation wavelengths from 200 to 600 nm. These measurements were compared to those of common, naturally occurring biological components like fungal spores and pollen and non spore samples like ovalbumin. The spectra of samples were combined into fluorescence profiles or fluorescence fingerprints. Different substrates were used for collection and detection of spores. Each bacterium produces a unique in vitro fluorescence profile when measured in dried and aqueous suspension and exhibits a strong maximum in its fluorescence emission spectrum near 330-340 nm. The fluorescence profiles were reproducible. The complexity of microorganisms made the interpretation of their spectral signature a difficult task. Principal components analysis (PCA) and cluster analysis were done as a data reduction technique for detection and identification from different backgrounds. PCA illustrates that linear combination of detected fluorescence intensities, which are present in different ratios in each of samples studied, can be used to discriminate biological agent simulants from other biological samples. The hydration effects, washing effects and the role of tryptophan on spore fluorescence were also investigated. The emission spectra of the dried spores showed a maximum near 330 nm, suggesting a hydrophobic environment for its tryptophan residues. The aqueous solution of tryptophan showed fluorescence shifted to 360 nm and in ethanol solution the maximum was shifted to 340 nm, suggesting a rather more polar average location of the tryptophan. To find the limit of detection we measured the quantum efficiency (QE) of a few samples. We concluded that spectroscopy techniques coupled with effective interpretation models are applicable to biological simulants agents. Index Heading: Bacteria; Spores; Identification; Fluorescence; Fluorescence Quantum Efficiency; Principal Components Analysis; Cluster Analysis.

Nonlinear limit cycle oscillators are common in nature and man-made equipments, for example, they occur in electronics, robotics, lasers, chemical reactions, biological systems and economical models. Such oscillators demonstrate periodic behavior with fixed frequency and amplitude independently of the system’s initial conditions. The goal of the doctoral thesis is the development and application of phase reduction and averaging methods to analyze particular nonlinear problems in self-oscillatory systems. The phase reduction method allows us to reduce the dynamic of a weakly perturbed limit cycle oscillator to a single scalar equation that defines the dynamics of the phase. This method is usually applied to the systems described by ordinary differential equations. Here this method is extended for the systems with time delay. The phase reduction method is applied to analyze the delayed feedback control (DFC) algorithm. Such an approach allows us to obtain analytical results for slightly mismatched DFC scheme and to stabilize unstable periodic orbits with topological restriction. The averaging method is applied to self-oscillatory systems driven by high-frequency periodic force. The method allows to derive the equations for the slow motion, averaged over high-frequency oscillations. Using this method the mechanism of suppression of sustained neuronal spiking under high frequency electrical stimulation is investigated. / Netiesiniai ribinio ciklo osciliatoriai dažnai sutinkami gamtoje bei žmogaus sukonstruotose sistemose, pavyzdžiui elektronikoje, robototechnikoje, lazeriuose, cheminėse reakcijose, biologinėse sistemose bei ekonominiuose modeliuose. Tokie osciliatoriai vaizduoja periodinį elgesį su fiksuotu dažniu ir amplitude nepriklausomai nuo sistemos pradinių sąlygų. Šios disertacijos tikslas yra išplėtoti ir pritaikyti fazinės redukcijos ir vidurkinimo metodus konkretiems uždaviniams spręsti. Fazinės redukcijos metodas leidžia silpnai perturbuoto ribinio ciklo osciliatoriaus dinamiką redukuoti iki vieno skaliarinio kintamojo dinamikos. Darbe fazinės redukcijos metodas išplėtotas ribinio ciklo osciliatoriams su delsa. Plačiai išnagrinėtas fazinės redukcijos taikymas chaotinėms sistemoms, kurių nestabili periodinė orbita (NPO) yra stabilizuojama uždelstuoju grįžtamuoju ryšiu (UGR). Toks priėjimas leidžia gauti analizinius rezultatus silpnai išderintai URG valdomai sistemai bei stabilizuoti NPO su topologiniu ribojimu. Vidurkinimo metodas leidžia gauti sistemos dinamiką, suvidurkintą per aukšto dažnio periodą, kai sistema yra veikiama aukšto dažnio periodine jėga. Darbe yra išnagrinėtas neuronų savųjų osciliacijų nuslopinimo mechanizmas, stimuliuojant juos aukšto dažnio elektriniu signalu.

Netiesiniai ribinio ciklo osciliatoriai dažnai sutinkami gamtoje bei žmogaus sukonstruotose sistemose, pavyzdžiui elektronikoje, robototechnikoje, lazeriuose, cheminėse reakcijose, biologinėse sistemose bei ekonominiuose modeliuose. Tokie osciliatoriai vaizduoja periodinį elgesį su fiksuotu dažniu ir amplitude nepriklausomai nuo sistemos pradinių sąlygų. Šios disertacijos tikslas yra išplėtoti ir pritaikyti fazinės redukcijos ir vidurkinimo metodus konkretiems uždaviniams spręsti. Fazinės redukcijos metodas leidžia silpnai perturbuoto ribinio ciklo osciliatoriaus dinamiką redukuoti iki vieno skaliarinio kintamojo dinamikos. Darbe fazinės redukcijos metodas išplėtotas ribinio ciklo osciliatoriams su delsa. Plačiai išnagrinėtas fazinės redukcijos taikymas chaotinėms sistemoms, kurių nestabili periodinė orbita (NPO) yra stabilizuojama uždelstuoju grįžtamuoju ryšiu (UGR). Toks priėjimas leidžia gauti analizinius rezultatus silpnai išderintai URG valdomai sistemai bei stabilizuoti NPO su topologiniu ribojimu. Vidurkinimo metodas leidžia gauti sistemos dinamiką, suvidurkintą per aukšto dažnio periodą, kai sistema yra veikiama aukšto dažnio periodine jėga. Darbe yra išnagrinėtas neuronų savųjų osciliacijų nuslopinimo mechanizmas, stimuliuojant juos aukšto dažnio elektriniu signalu. / Nonlinear limit cycle oscillators are common in nature and man-made equipments, for example, they occur in electronics, robotics, lasers, chemical reactions, biological systems and economical models. Such oscillators demonstrate periodic behavior with fixed frequency and amplitude independently of the system’s initial conditions. The goal of the doctoral thesis is the development and application of phase reduction and averaging methods to analyze particular nonlinear problems in self-oscillatory systems. The phase reduction method allows us to reduce the dynamic of a weakly perturbed limit cycle oscillator to a single scalar equation that defines the dynamics of the phase. This method is usually applied to the systems described by ordinary differential equations. Here this method is extended for the systems with time delay. The phase reduction method is applied to analyze the delayed feedback control (DFC) algorithm. Such an approach allows us to obtain analytical results for slightly mismatched DFC scheme and to stabilize unstable periodic orbits with topological restriction. The averaging method is applied to self-oscillatory systems driven by high-frequency periodic force. The method allows to derive the equations for the slow motion, averaged over high-frequency oscillations. Using this method the mechanism of suppression of sustained neuronal spiking under high frequency electrical stimulation is investigated.

We construct a mathematical model of an order driven market where traders can submit limit orders and market orders to buy and sell securities. We adapt the notion of no free lunch of Harrison and Kreps and Jouini and Kallal to our setting and we prove a no-arbitrage theorem for the model of the order driven market. Furthermore, we compute signatures of order books of different financial markets. Signatures, i.e. the full sequence of definite iterated integrals of a path, are one of the fundamental elements of the theory of rough paths. The theory of rough paths provides a framework to describe the evolution of dynamical systems that are driven by rough signals, including rough paths based on Brownian motion and fractional Brownian motion (see the work of Lyons). We show how we can obtain the solution of a polynomial differential equation and its (truncated) signature from the signature of the driving signal and the initial value. We also present and analyse an ODE method for the numerical solution of rough differential equations. We derive error estimates and we prove that it achieves the same rate of convergence as the corresponding higher order Euler schemes studied by Davie and Friz and Victoir. At the same time, it enhances stability. The method has been implemented for the case of polynomial vector fields as part of the CoRoPa software package which is available at http://coropa.sourceforge.net. We describe both the algorithm and the implementation and we show by giving examples how it can be used to compute the pathwise solution of stochastic rough differential equations driven by Brownian rough paths and fractional Brownian rough paths.

During the past 30 years, the proliferation of electronic trading has catalysed profound structural change in the global foreign exchange (FX) spot market. Today, more than 60% of the market's volume occurs via electronic trading platforms, which provide traders with round-the-clock market access from anywhere in the world. Such platforms offer several practical benefits that have encouraged market participation from a broad new class of financial institutions and have thereby spurred market growth. The most widely used electronic trading platforms in the FX spot market incorporate several features that differentiate them from those used in other financial markets. These features raise many important questions about order flow, market state, price formation, trader behaviour, and volatility. Despite the enormous trade volumes that such platforms facilitate, these questions have received almost no attention to date. In this thesis, we study a recent, high-quality data set from a large electronic trading platform in the FX spot market in order to investigate several aspects of trading via this mechanism. We calculate a wide range of statistics regarding order flow and market state, and we highlight how our findings contrast to those reported by empirical studies of electronic trading platforms in other markets. We study the autocorrelation properties of returns, absolute returns, and order flow, and we investigate the extent to which the market's organization impacts price formation. We also introduce a model designed to reproduce the most important properties of trading via such a platform. We derive several results regarding the model's temporal evolution, and we simulate the model to investigate how the interactions between individual traders influence volatility. We conclude that electronic trading platforms in the FX spot market retain many desirable features of centralized markets while providing traders with explicit control over their personal trading partnerships.

Incremental sheet forming (ISF) is a novel metal shaping technology that is economically viable for low-volume manufacturing, customisation and rapid-prototyping. It uses a small tool that is controlled by a computer-numerically controlled sequence and the path taken by this tool over the sheet defines the product geometry. Little is currently known about how to design the tool-path to minimise geometric errors in the formed part. The work here addresses this problem by developing a model based tool-path optimisation scheme for ISF. The key issue is how to generate an efficient model for ISF to use within a path optimisation routine, since current simulation methods are too slow. A proportion of this thesis is dedicated to evaluating the applicability of the rigid plastic assumption for this purpose. Three numerical models have been produced: one based on small strain deformation, one based on limit analysis theory and another that approximates the sheet to a network of rods. All three models are formulated and solved as second-order cone programs (SOCP) and the limit analysis based model is the first demonstration of an upper-bound shell finite element (FE) problem solved as an SOCP. The models are significantly faster than commercially available FE software and simulations are compared with experimental and numerical data, from which it is shown the rigid plastic assumption is suitable for modelling deformation in ISF. The numerical models are still too slow for the path optimisation scheme, so a novel linearised model based on the concept of spatial impulse responses is also formulated and used in an optimal control based tool-path optimisation scheme for producing axisymmetric products with ISF. Off-line and on-line versions of the scheme are implemented on an ISF machine and it is shown that geometric errors are significantly reduced when using the proposed method. This work provides a new structured framework for tool-path design in ISF and it is also a novel use of feedback to compensate for geometrical errors in ISF.

Actuellement, les objets communicants sans fils occupent une place prépondérante. Pour faciliter leur utilisation, ces objets sont de plus en plus petits et nécessitent de très petites antennes. Cette miniaturisation d’antennes implique forcément une détérioration de leurs performances. La conception d’antennes électriquement petites (AEP) nécessite une très bonne compréhension théorique des mécanismes électromagnétiques mis en jeu notamment quelles limites précises peut-on atteindre pour une AEP étant circonscrive dans un volume donné. Un des paramètres essentiels d’une AEP est son facteur de qualité intrinsèque qui est inversement proportionnel à sa bande passante en impédance. Ainsi, maximiser la bande passante en impédance d’une antenne consiste à minimiser son facteur de qualité. Face à ce problème, de nombreux travaux ont été développés pour déterminer les limites possibles pour des AEP. C’est dans ce cadre que s’inscrit le premier axe de recherche de la thèse : étudier le facteur de qualité d’AEP, afin de déterminer s’il existe des dimensions optimales permettant de s’approcher de ces limites. Le second axe de recherche a consisté à étudier des AEP fonctionnant à 2,45 GHz pour des implants biomédicaux. Celles-ci sont imprimées sur de nouveaux types de substrat pour avoir une meilleure résolution de trace métallique favorisant une réduction de l’encombrement, et une intégration facilitant ainsi les interconnexions avec les frontaux RF. Le challenge consiste à maximiser les performances de ces antennes. Plusieurs prototypes ont été réalisés pour valider les simulations. / Currently, wireless devices play an important role in everyday life. For ease-of-use, these devices are becoming smaller and require very small antennas. However, the size reduction of these antennas necessarily implies a degradation of their performance. Consequently, the design of electrically small antennas (ESA) requires a very good theoretical understanding of the electromagnetic phenomenon that takes place, especially in terms of accurate performance that can be expected for an ESA with given dimensions. An important parameter of an ESA is its intrinsic quality factor since it is inversely proportional to its impedance bandwidth. Indeed, maximizing the matching bandwidth of an antenna consists in minimizing its quality factor. Facing this problem, many researches have been developed to determine the possible limits of the quality factor of ESA. The first research axis of this thesis is to study the quality factor of ESA to determine whether optimal dimensions exist to approach the fundamental quality factor limits. The second part of the thesis studies miniature antennas for biomedical implants operating at 2.45 GHz. These antennas are printed on a specific microelectronic substrate to ensure a better resolution in terms of metallic traces in order to reduce the size and allow easier integration to facilitate interconnections with RF front-end. The challenge consists in maximizing the performance of these antennas. The presented results are supported by means of electromagnetic models and simulations on one hand. Also, several prototypes are fabricated to validate these simulations.

Les automates cellulaires sont à la fois un modèle de calcul parallèle, un système complexe et un système dynamique. Ils fonctionnent de manière synchrone et en temps discret, leur particularité est que les fonctions qu'ils définissent sont issues de l'application simultanée, en tout point de l'espace, d'une règle d'évolution locale. L'ensemble limite est un objet classique des systèmes dynamiques, c'est l'ensemble des états que le système peut atteindre arbitrairement tard. Il a été très étudié dans le cadre des automates cellulaires, et les résultats sont nombreux. Parmi ces résultats, un théorème de Rice démontré par Jarkko Kari dit que toute propriété des ensembles limites est indécidable. Dans ce mémoire, on ne s'intéresse plus à l'ensemble limite traditionnel, mais à une variante pour laquelle on utilise une mesure sur l'espace des entrées, sélectionnant ainsi les comportements susceptibles d'apparaître arbitrairement tard et souvent. Ce nouvel ensemble, que l'on nomme ensemble mu-limite, a été introduit en 2000 par Petr Kurka et Alejandro Maass. La plupart des résultats sur les ensembles limites ne se transposent pas naturellement. On étudie la famille des ensembles mu-limites d'automates cellulaires. On montre que sous certaines contraintes sur la dynamique, l'ensemble mu-limite peut être entièrement décrit. On classe ainsi les automates en fonction de ces contraintes. Dans le cas général, on montre l'existence d'automates cellulaires ayant comme ensembles mu-limites un grand nombre d'ensembles complexes. On finit par montrer un théorème de Rice pour les ensembles mu-limites d'automates cellulaires: tout propriété non triviale de ces ensembles est indécidable. / Cellular automata are simultaneously a model of parallel computation, a complex system and a dynamical system. They are synchronous and time is discrete. The functions defined by their application is the result of the synchronous application of the same local rule everywhere. The limit set is a classical tool of dynamical systems theory, it is the set of states the system can reach arbitrarily late. It has been studied often in the particular case of cellular automata and there are numerous results. Amongst them, a Rice's theorem proved by Jarkko Kari states that any non-trivial property of limit sets of cellular automata is undecidable. In this thesis, we do not consider the classical limit set, as we add a measure on the space of states of the system. Thus, we get a set which contains behaviors that appear arbitrarily far and often. This set is named mu-limit set and was introduced in 2000 by Petr Kurka and Alejandro Maass. Most of the results on limit sets cannot be directly adapted for mu-limit sets. We study the family of all mu-limit sets of cellular automata. We show that under some constraints on the dynamics, the mu-limit set can be entirely described. We then produce a classification of cellular automata according to these constraints. In the general case, we prove the existence of cellular automata whose mu-limit sets are among a large set of complex sets. We finally prove Rice's theorem for mu-limit sets: any non-trivial property is undecidable.