Substrate topography can have profound effects on initial bacterial adhesion during biofilm formation. We applied Staphylococcus epidermidis and Escherichia coli cells onto periodically structured substrates with different structure dimensions, structure types and wetting properties. We found a strong dependence of cell retention on the structure dimensions of the applied substrates. Periodicities in the range of the cell size increased, whereas smaller periodicities decreased cell retention, independent of contact time (minutes to hours) and hydrophobicity. These novel insights on the role of surface topography on bacterial retention might facilitate the development of non-fouling surfaces in the future.

This dissertation presents a self-contained study of periodically-driven quantum systems. Following a brief introduction to Floquet theory, we introduce the inverse-frequency expansion, variants of which include the Floquet-Magnus, van Vleck, and Brillouin-Wigner expansions. We reveal that the convergence properties of these expansions depend strongly on the rotating frame chosen, and relate the former to the existence of Floquet resonances in the quasienergy spectrum. The theoretical design and experimental realisation (`engineering') of novel Floquet Hamiltonians is discussed introducing three universal high-frequency limits for systems comprising single-particle and many-body linear and nonlinear models. The celebrated Schrieffer-Wolff transformation for strongly-correlated quantum systems is generalised to periodically-driven systems, and a systematic approach to calculate higher-order corrections to the Rotating Wave Approximation is presented. Next, we develop Floquet adiabatic perturbation theory from first principles, and discuss extensively the adiabatic state preparation and the corresponding leading-order non-adiabatic corrections. Special emphasis is thereby put on geometrical and topological objects, such as the Floquet Berry curvature and the Floquet Chern number obtained within linear response in the presence of the drive. Last, pre-thermalisation and thermalisation in closed, clean periodically-driven quantum systems are studied in detail, with the focus put on the crucial role of Floquet many-body resonances for energy absorption.

As embedded systems advance, the complexity and multifaceted requirements of products have increased significantly. A trend in this domain is the selection of different types of application models and multiprocessors as the platform. However, limited design space exploration techniques often perform one particular model, and combining diverse application models may cause compatibility issues. Additionally, embedded system design inherently involves multiple objectives. Beyond the essential functionalities, other metrics always need to be considered, such as power consumption, resource utilization, cost, safety, etc. The consideration of these diverse metrics results in a vast design space, so effective design space exploration also plays a crucial role. This thesis addresses these challenges by proposing a co-mapping approach for two distinct models: the periodically activated tasks model for real-time applications and the synchronous dataflow model for digital signal processing. Our primary goal is to co-map these two kinds of models onto a multi-core platform and explore trade-offs between the solutions. We choose the number of used resources and throughput of the synchronous dataflow model as our performance metrics for assessment. We adopt a combination method in which periodic tasks are given precedence to ensure their deadlines are met. The remaining processor resources are then allocated to the synchronous dataflow model. Both the execution of periodic tasks and the synchronous dataflow model are managed by a scheduler, which prevents resource contention and optimizes the utilization of available processor resources. To achieve a balance between different metrics, we implement Pareto optimization as a guiding principle in our approach. This thesis uses the IDeSyDe tool, an extension of the ForSyDe group’s current design space exploration tool, following the Design Space Identification methodology. Implementation is based on Scala and Python, running on the Java virtual machine. The experiment results affirm the successful mapping and scheduling of the periodically activated tasks model and the synchronous dataflow model onto the shared multi-processor platform. We find the Pareto-optimal solutions by IDeSyDe, strategically aiming to maximize the throughput of synchronous dataflow while concurrently minimizing resource consumption. This thesis serves as a valuable insight into the application of different models on a shared platform, particularly for developers interested in utilizing IDeSyDe. However, due to time constraints, our test case may not fully encompass the potential scalability of our thesis method. Additional tests can demonstrate the better effectiveness of our approach. For further reference, the code can be checked in the GitHub repository at*. / Allt eftersom inbyggda system utvecklas, blir komplexiteten och de mångfacetterade kraven av produkter har ökat avsevärt. En trend inom detta område är urval av olika typer av applikationsmodeller och multiprocessorer som plattformen. Dock begränsad design utrymme utforskning tekniker ofta utföra en viss modell, och kombinera olika applikationsmodeller kan orsaka kompatibilitetsproblem. Dessutom inbyggt systemdesign i sig involverar flera mål. Utöver de väsentliga funktionerna, andra mätvärden måste alltid beaktas, såsom strömförbrukning, resurs användning, kostnad, säkerhet, etc. Övervägandet av dessa olika mätvärden resulterar i ett stort designutrymme spelar så effektiv designrumsutforskning också en avgörande roll roll. Denna avhandling tar upp dessa utmaningar genom att föreslå en samkartläggning tillvägagångssätt för två distinkta modeller: modellen med periodiskt aktiverade uppgifter för realtidsapplikationer och den synkrona dataflödesmodellen för digital signal bearbetning. Vårt primära mål är att samkarta dessa två typer av modeller på en multi-core plattform och utforska avvägningar mellan lösningarna. Vi väljer antalet använda resurser och genomströmning av det synkrona dataflödet modell som vårt prestationsmått för bedömning. Vi använder en kombinationsmetod där periodiska uppgifter ges företräde för att säkerställa att deras tidsfrister hålls. Den återstående processorn resurser allokeras sedan till den synkrona dataflödesmodellen. Både utförandet av periodiska uppgifter och den synkrona dataflödesmodellen är hanteras av en schemaläggare, vilket förhindrar resursstrid och optimerar utnyttjandet av tillgängliga processorresurser. För att uppnå en balans mellan olika mått, implementerar vi Pareto-optimering som en vägledande princip i vårt tillvägagångssätt. Denna avhandling använder verktyget IDeSyDe, en förlängning av ForSyDe gruppens nuvarande verktyg för utforskning av designutrymme, efter Design Space Identifieringsmetodik. Implementeringen är baserad på Scala och Python, körs på den virtuella Java-maskinen. Experimentresultaten bekräftar den framgångsrika kartläggningen och schemaläggningen av den periodiskt aktiverade uppgiftsmodellen och det synkrona dataflödet modell på den delade flerprocessorplattformen. Vi finner Pareto-optimal lösningar av IDeSyDe, strategiskt inriktade på att maximera genomströmningen av synkront dataflöde samtidigt som resursförbrukningen minimeras. Denna uppsats fungerar som en värdefull inblick i tillämpningen av olika modeller på en delad plattform, särskilt för utvecklare IDeSyDe. På grund av tidsbrist kanske vårt testfall inte är fullt ut omfattar den potentiella skalbarheten hos vår avhandlingsmetod. Ytterligare tester kan visa hur effektiv vår strategi är. För ytterligare referens, koden kan kontrolleras i GitHub*.

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Le secteur de communications sécurisés et portables connait une véritable révolution avec l’apparition des plateformes dites radios logiciels (Software Defined Radios, SDRs). Les performances exceptionnelles de ces systèmes sont les résultats d’une interaction assez complexe et souvent peu évidente entre le logiciel embarqué, le circuit de traitement numérique et les blocs mixtes analogiques/RF. Cette complexité limite la testabilité du produit fini. La méthodologie de test utilisée actuellement a atteint ses limites dues au cout élevé, le long temps de test et le bas degré de généralisation. De plus, les plateformes SDRs peuvent évoluer sur le terrain et elles vont supporter des standards et des scénarios qui n’ont pas été considérés pendant le la phase de conception. Donc, une stratégie de test sur le terrain (en ligne) n’est plus une caractéristique optionnelle mais une nécessité. Dans ce contexte, le but de notre recherche est d’inventer et développer une méthodologie de test capable de garantir le bon fonctionnement d’une plateforme SDR après la production et pendant sa vie. Notre objectif final est de réduire le coût du test en profitant de la reconfigurabilité de la plateforme. Pour les radios tactiques qui doivent être mises à jour sur le terrain sans équipement spécial, les stratégies Built-In Self-Test (BIST) sont, sans doute, la seule moyenne de garantir la conformité aux spécifications. Dans cette mémoire, nous introduisons une nouvelle architecture de test RF BIST qui utilise la technique de de sous-échantillonnage nonuniform à la sortie de l’émetteur (TX) d’une SDR afin d’évaluer la conformité de la masque spectrale. Notre solution s’appuie sur une implémentation autonome, est modulable et peut être appliquée pour le test sur le terrain avec des modifications minimes. Par rapport aux autres techniques de test analogiques/RF, cet approche ne dépends pas de la architecture du TX, ni d’un modèle ad-hoc, ce qui est idéale pour le test des SDRs. / The advent of increasingly powerful Integrated Circuits (IC) has led to the emergence of the Software Defined Radio (SDR) concept, which brought the sector of secured mobile communications into a new era. The outstanding performance of these systems results from optimal trade-offs among advanced analog/Radio Frequency (RF) circuitry, high-speed reconfigurable digital hardware and sophisticated real-time software. The inherent sophistication of such platforms poses a challenging problem for product testing. Currently deployed industrial test strategies face rising obstacles due to the costlier RF test equipment, longer test time and lack of flexibility. Moreover, an SDR platform is field-upgradeable, which means it will support standards and scenarii not considered during the design phase. Therefore, an in-field test strategy is not anymore 'a nice to have' feature but a mandatory requirement. In this context, our research aims to invent and develop a new test methodology able to guarantee the correct functioning of the SDR platform post-fabrication and over its operational lifetime. The overall aim of our efforts is to reduce post-manufacture test cost of SDR transceivers by leveraging the reconfigurability of the platform.For tactical radio units that must be field-upgradeable without specialized equipment, Built-in Self-Test (BIST) schemes are arguably the only way to ensure continued compliance to specifications. In this study we introduce a novel RF BIST architecture which uses Periodically Nonuniform Sampling (PNS2) of the transmitter (TX) output to evaluate compliance to spectral mask specifications. Our solution supports a stand-alone implementation, is scalable across a wide set of complex specifications and can be easily applied for in-field testing with small added hardware. Compared to existing analog/RF test techniques, this approach is not limited to a given TX architecture and does not rely on an ad-hoc TX model, which makes it ideal for SDR testing.

Le secteur de communications sécurisés et portables connait une véritable révolution avec l’apparition des plateformes dites radios logiciels (Software Defined Radios, SDRs). Les performances exceptionnelles de ces systèmes sont les résultats d’une interaction assez complexe et souvent peu évidente entre le logiciel embarqué, le circuit de traitement numérique et les blocs mixtes analogiques/RF. Cette complexité limite la testabilité du produit fini. La méthodologie de test utilisée actuellement a atteint ses limites dues au cout élevé, le long temps de test et le bas degré de généralisation. De plus, les plateformes SDRs peuvent évoluer sur le terrain et elles vont supporter des standards et des scénarios qui n’ont pas été considérés pendant le la phase de conception. Donc, une stratégie de test sur le terrain (en ligne) n’est plus une caractéristique optionnelle mais une nécessité. Dans ce contexte, le but de notre recherche est d’inventer et développer une méthodologie de test capable de garantir le bon fonctionnement d’une plateforme SDR après la production et pendant sa vie. Notre objectif final est de réduire le coût du test en profitant de la reconfigurabilité de la plateforme. Pour les radios tactiques qui doivent être mises à jour sur le terrain sans équipement spécial, les stratégies Built-In Self-Test (BIST) sont, sans doute, la seule moyenne de garantir la conformité aux spécifications. Dans cette mémoire, nous introduisons une nouvelle architecture de test RF BIST qui utilise la technique de de sous-échantillonnage nonuniform à la sortie de l’émetteur (TX) d’une SDR afin d’évaluer la conformité de la masque spectrale. Notre solution s’appuie sur une implémentation autonome, est modulable et peut être appliquée pour le test sur le terrain avec des modifications minimes. Par rapport aux autres techniques de test analogiques/RF, cet approche ne dépends pas de la architecture du TX, ni d’un modèle ad-hoc, ce qui est idéale pour le test des SDRs. / The advent of increasingly powerful Integrated Circuits (IC) has led to the emergence of the Software Defined Radio (SDR) concept, which brought the sector of secured mobile communications into a new era. The outstanding performance of these systems results from optimal trade-offs among advanced analog/Radio Frequency (RF) circuitry, high-speed reconfigurable digital hardware and sophisticated real-time software. The inherent sophistication of such platforms poses a challenging problem for product testing. Currently deployed industrial test strategies face rising obstacles due to the costlier RF test equipment, longer test time and lack of flexibility. Moreover, an SDR platform is field-upgradeable, which means it will support standards and scenarii not considered during the design phase. Therefore, an in-field test strategy is not anymore 'a nice to have' feature but a mandatory requirement. In this context, our research aims to invent and develop a new test methodology able to guarantee the correct functioning of the SDR platform post-fabrication and over its operational lifetime. The overall aim of our efforts is to reduce post-manufacture test cost of SDR transceivers by leveraging the reconfigurability of the platform.For tactical radio units that must be field-upgradeable without specialized equipment, Built-in Self-Test (BIST) schemes are arguably the only way to ensure continued compliance to specifications. In this study we introduce a novel RF BIST architecture which uses Periodically Nonuniform Sampling (PNS2) of the transmitter (TX) output to evaluate compliance to spectral mask specifications. Our solution supports a stand-alone implementation, is scalable across a wide set of complex specifications and can be easily applied for in-field testing with small added hardware. Compared to existing analog/RF test techniques, this approach is not limited to a given TX architecture and does not rely on an ad-hoc TX model, which makes it ideal for SDR testing.

科学研究費補助金 研究種目:基盤研究(C)(2) 課題番号:09640721 研究代表者:野水 勉 研究期間:1997-1998年度

MENEZES, José Wally Mendonça. Análise de performance de sólitons ópticos espaço-temporais em guia planar com não-linearidade cúbico quintica periodicamente modulada e circuitos lógicos operando nos regimes Kerr instantâneo e relaxado. 2010. 149 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2010. / Submitted by francisco lima (admir@ufc.br) on 2014-06-30T18:38:52Z No. of bitstreams: 1 2010_tese_jwmmenezes.pdf: 7446687 bytes, checksum: 708020e7c4ad24658a46a55f2af5ebc6 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2014-08-06T20:53:00Z (GMT) No. of bitstreams: 1 2010_tese_jwmmenezes.pdf: 7446687 bytes, checksum: 708020e7c4ad24658a46a55f2af5ebc6 (MD5) / Made available in DSpace on 2014-08-06T20:53:00Z (GMT). No. of bitstreams: 1 2010_tese_jwmmenezes.pdf: 7446687 bytes, checksum: 708020e7c4ad24658a46a55f2af5ebc6 (MD5) Previous issue date: 2010 / In this work, the propagation and stability of spatiotemporal optical solitons (or optical bullets) in a planar waveguide with periodically modulated cubic-quintic nonlinearity is presented numerically as a function of the amplitudes of modulation , the frequency of modulation and the propagation distance .With the objective of ensure the stability and preventing the collapse or the spreading of pulses, in this study we explore the cubic-quintic nonlinearity with the optical fields coupled by XPM (Cross-Phase Modulation) and take into account several values for the nonlinear parameter , for amplitudes and frequency of modulation as a function of the propagation distance , we cause the collisions of two pulses (envelope of the optical field) to ensure that the optical pulse are sólitons and, after numerical analysis was possible shown the existence of stable spatiotemporal optical sóliton. We also have presented the numerical analysis of the three-core nonlinear fiber coupler in a symmetrical planar structure and operating with instantaneous and relaxed Kerr model for generation of the all-optical logic gates. To implement this optical circuit, we used a control pulse CP with a phase difference between the inputs “I1” and “I2” of the fiber coupler and were analyzed the transmission characteristics, the Extinction Ratio as a function of the phase difference, the length normalized (LN), the figure-of-merit of the logic gates (FOMELG (dB) and the pulse evolution along the fiber coupler and, thus, ensure were demonstrated the possibilities for generating of the all-optical logic gates. / Neste trabalho, a propagação e estabilidade de sólitons espaço-temporais (ou sólitons balas) em um guia de onda planar com não linearidade cúbico quintica periodicamente modulada é apresentada em função da amplitude de modulação , da freqüência de modulação e da distância de propagação . Com o objetivo de garantir a estabilidade e prevenir o colapso ou o espalhamento dos pulsos, exploramos a não-linearidade cúbico quintica com os campos ópticos acoplados por XPM (Modulação de Fase Cruzada) e utilizando diversos valores para o parâmetro não-linear , para as amplitudes e freqüências de modulação em função da distância de propagação , provocamos a colisão de dois pulsos (campos ópticos) para garantir que estes sejam realmente sólitons e, após estas análises numéricas, foi possível mostrar a existência de sólitons espaço-temporais estáveis. Apresentamos, também, a análise numérica de um acoplador triplo não linear de fibras ópticas em uma estrutura planar simétrica e operando com o modelo Kerr instantâneo e relaxado para geração de portas lógicas ópticas. Para implementar estes circuitos, usamos um pulso de controle CP com uma diferença de fase entre as entradas “I1” e “I2” do acoplador e analisamos as características de transmissão, taxa de extinção em função da diferença de fase, a largura normalizada (LN), a figura de mérito para portas lógicas FOMELG(dB) e a evolução dos pulsos ao longo do acoplador e, assim, foi demonstrado as possibilidades para geração das portas lógicas ópticas.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Neste trabalho, a propagaÃÃo e estabilidade de sÃlitons espaÃo-temporais (ou sÃlitons balas) em um guia de onda planar com nÃo linearidade cÃbico quintica periodicamente modulada à apresentada em funÃÃo da amplitude de modulaÃÃo , da freqÃÃncia de modulaÃÃo e da distÃncia de propagaÃÃo . Com o objetivo de garantir a estabilidade e prevenir o colapso ou o espalhamento dos pulsos, exploramos a nÃo-linearidade cÃbico quintica com os campos Ãpticos acoplados por XPM (ModulaÃÃo de Fase Cruzada) e utilizando diversos valores para o parÃmetro nÃo-linear , para as amplitudes e freqÃÃncias de modulaÃÃo em funÃÃo da distÃncia de propagaÃÃo , provocamos a colisÃo de dois pulsos (campos Ãpticos) para garantir que estes sejam realmente sÃlitons e, apÃs estas anÃlises numÃricas, foi possÃvel mostrar a existÃncia de sÃlitons espaÃo-temporais estÃveis. Apresentamos, tambÃm, a anÃlise numÃrica de um acoplador triplo nÃo linear de fibras Ãpticas em uma estrutura planar simÃtrica e operando com o modelo Kerr instantÃneo e relaxado para geraÃÃo de portas lÃgicas Ãpticas. Para implementar estes circuitos, usamos um pulso de controle CP com uma diferenÃa de fase entre as entradas âI1â e âI2â do acoplador e analisamos as caracterÃsticas de transmissÃo, taxa de extinÃÃo em funÃÃo da diferenÃa de fase, a largura normalizada (LN), a figura de mÃrito para portas lÃgicas FOMELG(dB) e a evoluÃÃo dos pulsos ao longo do acoplador e, assim, foi demonstrado as possibilidades para geraÃÃo das portas lÃgicas Ãpticas. / In this work, the propagation and stability of spatiotemporal optical solitons (or optical bullets) in a planar waveguide with periodically modulated cubic-quintic nonlinearity is presented numerically as a function of the amplitudes of modulation , the frequency of modulation and the propagation distance .With the objective of ensure the stability and preventing the collapse or the spreading of pulses, in this study we explore the cubic-quintic nonlinearity with the optical fields coupled by XPM (Cross-Phase Modulation) and take into account several values for the nonlinear parameter , for amplitudes and frequency of modulation as a function of the propagation distance , we cause the collisions of two pulses (envelope of the optical field) to ensure that the optical pulse are sÃlitons and, after numerical analysis was possible shown the existence of stable spatiotemporal optical sÃliton. We also have presented the numerical analysis of the three-core nonlinear fiber coupler in a symmetrical planar structure and operating with instantaneous and relaxed Kerr model for generation of the all-optical logic gates. To implement this optical circuit, we used a control pulse CP with a phase difference between the inputs âI1â and âI2â of the fiber coupler and were analyzed the transmission characteristics, the Extinction Ratio as a function of the phase difference, the length normalized (LN), the figure-of-merit of the logic gates (FOMELG (dB) and the pulse evolution along the fiber coupler and, thus, ensure were demonstrated the possibilities for generating of the all-optical logic gates.

Periodically perforated sheets(PS) are ubiquitous in nature as well as in engineered artifacts developed for aerospace, automotive, marine, nuclear and structural applications. PS are indispensable for saving weight and cost for aircraft; for enhancing safety and integrity of heat exchangers used in nuclear and thermal power stations. Ancient PS grills and lattice frames dating back to 1000 BC continue to inspire contemporary art and architecture, buildings and furniture. PS design and analysis, however, is a complex affair stemming from the inherent configurational anisotropy induced by periodicity. In addition, complex boundary conditions complicate the analysis. Unlike atoms in crystalline media, both shape and periodicity of perforations control this anisotropic nature. This thesis explores theoretical and numerical strategies for evaluating the effective anisotropic elastic moduli of PS. Following an experimental prelude for visualizing the PS stress field in a photoelastic sheet and a brief review of PS theory, this thesis proposes a novel theoretical numerical hybrid method for determining the Airy stress function constants. The proposed hybrid method can be exploited experimentally using automated vision based imaging technologies to measure the boundary displacements noninvasively. For determining the Airy constants periodic boundary conditions to the unit cell are applied, the displacement components around the PS hole boundary are obtained using FEM. Using these constants the PS stress field is reconstructed to assess the efficacy of the proposed hybrid method. It is observed that in general while the actual and the reconstructed stress fields agree reasonably well, more refined boundary data obtained either numerically or experimentally can enhance the accuracy further. The thesis then makes an extensive presentation of anisotropic moduli in a variety of PS designs configured on rectangular or square layouts. Conventional as well as some exotic patterns with cusps and satellite holes are examined, and the results are presented graphically to aid the designer. Finally, some special topics pertaining PS design and analysis are discussed to help overcome the inherent limitations of solutions based on applying periodic boundary conditions. In this vein, strategies for achieving a functionally graded PS are presented by altering the pitch and hole size. These strategies assume importance near boundaries as well as near concentrated forces inducing stress gradients. Other special topics include the applicability of tensor transformation rule to PS anisotropy. The effective bulk modulus which remains a scalar invariant is exploited to assess the validity of tensor transformation in a square PS. The rule of mixture widely used in homogenization of composite media is also discussed briefly. Thus, this thesis makes an attempt to demonstrate the power of blending micromechanics with experiments and FEM to aid in PS design and analysis.