Long-haul optical fiber communication system is an important technology to support the latest broadband communication in the world, and there is strong competition in optical long-haul transmission to achieve high channel bit rates and large transmission capacity. Therefore, it is important to study a technology to improve the performance of such system. As we have already known, return-to-zero differential phase shift keying (RZ-DPSK) is an attractive solution to improve the long distance transmission system performance compared to the conventional on-off keying (OOK) in a 10-Gb/s system, because it has a high nonlinear tolerance. The dispersion flattened fiber (DFF) is attractive for its ability to improve the system performance. Therefore, it is possible to improve the transmission performance by a combination of the RZ-DPSK and the DFF, and one important technology of the current long-haul optical fiber communication system is the dispersion map. And it is widely deployed for already installed undersea optical fiber communication system in the world. A previous study reported that the blockless type dispersion map showed a superior performance than the block type dispersion map, and some efforts to improve the transmission performance of the block type map were conducted. Fundamental idea to improve the transmission performance of the block type map is to reduce the zero crossing points, and one idea is to shift the map toward the positive or the negative cumulative dispersion to reduce the zero crossing points within the map, but it was not so successful. The other idea is to tilt the dispersion map and it was more successful but not good enough. In this master thesis, I continued the study to improve the long-haul RZ-DPSK system performance using the block type dispersion map. One new idea of the dispersion map shifting, the split shifting, was tried, and another new idea of the dispersion map tilting, the split tilting, was examined. The performance with different repeater output power and different compensation scheme within the dispersion map was simulated by a numerical simulator .The goal is, following previous research, to clarify improved dispersion map design of the long-haul RZ-DPSK based transmission and find the effective method to improve the transmission performance. In addition, I also investigate tolerance of the effective area of the transmission fiber theoretically for the long-haul RZ-DPSK system based on the DFF.

The mass transfer area of nine structured packings was measured as a function of liquid load, surface tension, liquid viscosity, and gas rate in a 0.427 m (16.8 in) ID column via absorption of CO₂ from air into 0.1 mol/L NaOH. Surface tension was decreased from 72 to 30 mN/m via the addition of a surfactant (TERGITOL[trademark] NP-7). Viscosity was varied from 1 to 15 mPa·s using poly(ethylene oxide) (POLYOX[trademark] WSR N750). A wetted-wall column was used to verify the kinetics of these systems. Literature model predictions matched the wetted-wall column data within 10%. These models were applied in the interpretation of the packing results. The packing mass transfer area was most strongly dictated by geometric area (125 to 500 m²/m³) and liquid load (2.5 to 75 m³/m²·h or 1 to 30 gpm/ft²). A reduction in surface tension enhanced the effective area. The difference was more pronounced for the finer (higher surface area) packings (15 to 20%) than for the coarser ones (10%). Gas velocity (0.6 to 2.3 m/s), liquid viscosity, and channel configuration (45° vs. 60° or smoothed element interfaces) had no appreciable impact on the area. Surface texture (embossing) increased the area by 10% at most. The ratio of effective area to specific area (a[subscript e]/a[subscript p]) was correlated within limits of ±13% for the experimental database: [mathematical formula]. This area model is believed to offer better predictive accuracy than the alternatives in the literature, particularly under aqueous conditions. Supplementary hydraulic measurements were obtained. The channel configuration significantly impacted the pressure drop. For a 45°-to-60° inclination change, pressure drop decreased by more than a factor of two and capacity expanded by 20%. Upwards of a two-fold increase in hold-up was observed from 1 to 15 mPa·s. Liquid load strongly affected both pressure drop and hold-up, increasing them by several-fold over the operational range. An economic analysis of an absorber in a CO₂ capture process was performed. Mellapak[trademark] 250X yielded the most favorable economics of the investigated packings. The minimum cost for a 7 m MEA system was around $5-7/tonne CO₂ removed for capacities in the 100 to 800 MW range. / text

Le Large Area Telescope à bord du satellite Fermi, lancé le 11 juin 2008, est un télescope spatial observant l'univers des hautes énergies. L'instrument couvre l'intervalle en énergie de 20MeV à 300GeV avec une sensibilité nettement améliorée et la capacité de localiser des sources ponctuelles. Il détecte les photons ? par leur conversion en paire électron- positron, et mesure leur direction et leur énergie grâce à un trajectographe et un calorimètre. Cette thèse présente les courbes de lumières et les mesures spectrales résolues en phase des pulsars radio et gamma détectés par le LAT. La mesure des paramètres spectraux (flux, indice spectral, et énergie de coupure) dépend des fonctions de réponse de l'instrument (IRFs). Une méthode développée pour la validation en orbite de la surface efficace est présentée en utilisant le pulsar de Vela. Les efficacités des coupures entre les données du LAT et les données simulées sont comparées à chaque niveau de la rejection du fond. Les résultats de cette analyse sont propagés vers les IRFs pour évaluer les systématiques des mesures spectrales. La dernière partie de cette thèse présente les découvertes de nouveaux pulsars ? individuels tels que PSR J0205+6449, J2229+6114, et J1048-5832 à partir des données du LAT et des éphémérides radio et X. Des analyses temporelles et spectrales sont investies dans le but de contraindre les modèles d'émission gamma. Finalement, nous discutons les propriétés d'une large population de pulsars gamma détectés par le LAT, incluant les pulsars normaux et les pulsars milliseconde. / The Large Area Telescope (LAT) on Fermi, launched on 2008 June 11, is a space telescope to explore the high energy ?-ray universe. The instrument covers the energy range from 20MeV to 300GeV with greatly improved sensitivity and ability to localize ?-ray point sources. It detects ?-rays through conversion to electron-positron pairs and measurement of their direction in a tracker and their energy in a calorimeter. This thesis presents the ?-ray light curves and the phase-resolved spectral measurements of radio-loud gamma-ray pulsars detected by the LAT. The measurement of pulsar spectral parameters (i.e. integrated flux, spectral index, and energy cut-off) depends on the instrument response functions (IRFs). A method developed for the on-orbit validation of the effective area is presented using the Vela pulsar. The cut efficiencies between the real data and the simulated data are compared at each stage of the background rejection. The results are then propagated to the IRFs, allowing the systematic uncertainties of the spectral parameters to be estimated. The last part of this thesis presents the discoveries, using both the LAT observations and the radio and X ephemeredes, of new individual ?-ray pulsars such as PSR J0205+6449, and the Vela-like pulsars J2229+6114 and J1048-5832. Timing and spectral analysis are investigated in order to constrain the ?-ray emission model. In addition, we discuss the properties of a large population of ?-ray pulsars detected by the LAT, including normal pulsars, and millisecond pulsars.

Nowadays, the long-haul optical fiber communication system is one of the important way to convey the information, and there is strong competition of research in the optical long-haul transmission to achieve high channel bit rates and large transmission capacity. Therefore, it is important to study a technology to improve the performance of such system. The return-to-zero differential phase-shift keying (RZ-DPSK) and the return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) have received renewed attention recently for the long-haul transmission systems, because they can improve the transmission performance of the long-haul system. Furthermore, the design of the dispersion map becomes significantly different from that of the conventional system using the intensity modulation direct detection (IM-DD) scheme. Besides, the RZ-DQPSK can transmit two bits per symbol, so it has twice the spectral efficiency of the RZ-DPSK. This study is focusing on the difference of the transmission performance of the long-haul RZ-DQPSK system due to the dispersion map using the numerical simulation.

This thesis addresses the potential of implementing a predriver for class-D power amplifier for WLAN in 65 nm CMOS technology. In total, eight different predrivers have been created using Cadence Virtuoso CAD tools. All designs have been tested using Agilent's Advance Design System (ADS) and simulated using the ADS-Cadence dynamic link. Furthermore, a comparison between the eight designs and the reference design has been done. The examined parameters were output power (Pout), efficiency, and effective area consumption. The simulation results show that most of the proposed designs obtain higher output power, higher efficiency, and lower effective area than the reference design. For the reference design, output power of 34.2 dBm, efficiency of 20.8 %, and effective area of 63952 um2 were obtained. For design No.1, the effective area was 31511um2, which was almost half of the area occupied by the reference design. For design No.3, the efficiency was 71.2 %, which was almost 3 and half times higher than the efficiency of the reference design. Furthermore, all designs, except design NO.7, gave more or less the same output power (around 34.4 dBm).

Radio astronomy is used to study stars, galaxies, black holes and gas clouds radiation at radio frequencies. Detecting extremely weak signals from deep space radio sources requires high sensitive feed system associated with large dish antennas. The key figure of merit is survey speed, or the time required to map a region of the sky to a given source flux density. Survey speed is proportional to the frequency bandwidth, the field of view or observable region of the sky, and the squared sensitivity, where sensitivity is related to reflector aperture efficiency and system noise temperature. Compared to the traditional single feed, phased array feeds with significantly expanded field of view are considered as the next generation feed for radio telescope. This dissertation outlines the design, analysis and measurement of high sensitivity L-band and mm-wave phased array feeds for the 100-meter Green Bank Telescope. Theoretical works for radio astronomy includes design guideline for high sensitivity phased array feed, fundamental frequency bandwidth limit, array antenna loss influenced by mutual coupling and beamformer coefficients and possibility of superdirectivity for radio telescopes and other antennas. These study are helpful to understand and guide the design of a phased array feed system. In the absence of dish antennas, sparse phased arrays with aperiodic structure have been developed for satellite communications. A compromise between the peak side lobe level, array element density, directivity and design complexity is studied. We have found that the array peak side lobe level can be reduced by enhancing the array element direction at the main lobe direction, increasing the array element density and enlarging the array size. A Poynting streamline approach develops to understand the properties of a receiving antenna and the mutual coupling effects between array elements. This method has been successfully used to generate effective area shape for many types of antennas and guide the design of a superdirective antenna. Motivated by this method, a superdirective antenna is experimental demonstrated.

As áreas protegidas são consideradas pilares para estratégias de conservação da diversidade biológica. Presume-se que a distribuição destas áreas representa a proteção de espécies e ecossistemas. Dentre as 20 metas globais para a redução da perda de biodiversidade, a Meta 11 de áreas protegidas estabelece, dentre outros aspectos, que 17% das áreas terrestres devem ser cobertas por sistemas de áreas protegidas ecologicamente representativos, efetivos, conectados e integrados a paisagens terrestres mais amplas. Neste estudo avaliou-se a representatividade ecológica, a efetividade e a integração a paisagens mais amplas do sistema de unidades de conservação, e perspectivas para subsidiar a sua ampliação no bioma Pampa. Além das unidades de conservação stricto senso, em parte das análises também foram considerados os sistemas complementares de terras indígenas e mecanismos de preservação em propriedades rurais definidos pela Lei de Proteção da Vegetação Nativa. A avaliação da representatividade foi feita considerando o Pampa (nível nacional) e também os 11 sistemas ecológicos presentes no bioma (nível regional). Foram levantadas 53 unidades de conservação no Pampa, com cobertura total de 3,23% do bioma Os mecanismos de preservação em propriedades rurais têm potencial de ampliar o sistema de áreas protegidas para até 9,64%, porém ainda depende de validação do órgão ambiental. O percentual protegido por unidades de conservação nos sistemas ecológicos variou entre 0% e 17,76%, sendo que nove dos 11 sistemas possuem menos de 3% em unidades de conservação. Os dados indicaram que as unidades são relativamente efetivas, pois 64% delas mantiveram ou recuperaram sua cobertura de vegetação nativa. As análises sugerem ainda, que a efetividade associada à cobertura vegetal no interior das unidades possui uma relação com a dinâmica no seu entorno. De forma geral, as unidades sofrem influência das alterações no uso da terra em suas adjacências. Para manutenção da efetividade da unidade de conservação, a unidade deve ser manejada considerando essas influências do entorno. Na perspectiva de ampliação do sistema, o esforço para conservação deve ser centrado na criação de novas unidades de conservação e diversificação de categorias. Os dados aqui obtidos indicam que o Pampa dificilmente alcançará a meta de 17% em um sistema de áreas protegidas ecologicamente representativo até 2020. / Protected areas are considered cornerstones for biodiversity conservation strategies. It is presumed that the distribution of these areas represents the protection of species and ecosystems. Among the 20 global targets for reducing biodiversity loss, Target 11 establishes that 17% of land areas must be covered by ecologically representative, effective and connected systems integrated to wider terrestrial landscapes, among other aspects. This study assessed ecological representativeness, effectiveness, and integration of protected area system, into wider landscapes of the Pampa biome. Perspectives to subsidize protected area expansion were also considered here. The representativeness assessment was made by considering the Pampa (national level) and also the 11 ecological systems present in the biome (regional level). Complementary systems of indigenous lands and mechanisms of preservation in rural properties defined by the Law of Protection of Native Vegetation was considered for the national level. Fifty-three protected areas were found in Pampa, with a total coverage of 3.23% of the biome Preservation mechanisms on rural properties have the potential to extend Pampa protected area system to up to 9.64%, but still depend on the environmental agencies validation. The percentage protected by protected areas in ecological systems ranged from zero to 17.76%, and nine of the 11 systems have less than 3% in protected areas. Data indicated that protected areas are relatively effective since 64% of them maintained or recovered their native vegetation cover. Data also indicated that protected area effectiveness has a relation to the dynamics in its surroundings regarding land use and vegetation cover. It is possible to affirm that Pampa protected areas are influenced by changes in land use in their vicinity. Protected areas must be managed considering these environmental influences to maintain their effectiveness. In perspective of expansion of the protected area system, the effort for conservation should be centered on the establishment of new protected areas with the diversification of management categories and in ecological systems with low percentages of protected areas cover. Data obtained here indicates that Pampa is unlikely to reach the 17% target in an ecologically representative protected area system by 2020.

As áreas protegidas são consideradas pilares para estratégias de conservação da diversidade biológica. Presume-se que a distribuição destas áreas representa a proteção de espécies e ecossistemas. Dentre as 20 metas globais para a redução da perda de biodiversidade, a Meta 11 de áreas protegidas estabelece, dentre outros aspectos, que 17% das áreas terrestres devem ser cobertas por sistemas de áreas protegidas ecologicamente representativos, efetivos, conectados e integrados a paisagens terrestres mais amplas. Neste estudo avaliou-se a representatividade ecológica, a efetividade e a integração a paisagens mais amplas do sistema de unidades de conservação, e perspectivas para subsidiar a sua ampliação no bioma Pampa. Além das unidades de conservação stricto senso, em parte das análises também foram considerados os sistemas complementares de terras indígenas e mecanismos de preservação em propriedades rurais definidos pela Lei de Proteção da Vegetação Nativa. A avaliação da representatividade foi feita considerando o Pampa (nível nacional) e também os 11 sistemas ecológicos presentes no bioma (nível regional). Foram levantadas 53 unidades de conservação no Pampa, com cobertura total de 3,23% do bioma Os mecanismos de preservação em propriedades rurais têm potencial de ampliar o sistema de áreas protegidas para até 9,64%, porém ainda depende de validação do órgão ambiental. O percentual protegido por unidades de conservação nos sistemas ecológicos variou entre 0% e 17,76%, sendo que nove dos 11 sistemas possuem menos de 3% em unidades de conservação. Os dados indicaram que as unidades são relativamente efetivas, pois 64% delas mantiveram ou recuperaram sua cobertura de vegetação nativa. As análises sugerem ainda, que a efetividade associada à cobertura vegetal no interior das unidades possui uma relação com a dinâmica no seu entorno. De forma geral, as unidades sofrem influência das alterações no uso da terra em suas adjacências. Para manutenção da efetividade da unidade de conservação, a unidade deve ser manejada considerando essas influências do entorno. Na perspectiva de ampliação do sistema, o esforço para conservação deve ser centrado na criação de novas unidades de conservação e diversificação de categorias. Os dados aqui obtidos indicam que o Pampa dificilmente alcançará a meta de 17% em um sistema de áreas protegidas ecologicamente representativo até 2020. / Protected areas are considered cornerstones for biodiversity conservation strategies. It is presumed that the distribution of these areas represents the protection of species and ecosystems. Among the 20 global targets for reducing biodiversity loss, Target 11 establishes that 17% of land areas must be covered by ecologically representative, effective and connected systems integrated to wider terrestrial landscapes, among other aspects. This study assessed ecological representativeness, effectiveness, and integration of protected area system, into wider landscapes of the Pampa biome. Perspectives to subsidize protected area expansion were also considered here. The representativeness assessment was made by considering the Pampa (national level) and also the 11 ecological systems present in the biome (regional level). Complementary systems of indigenous lands and mechanisms of preservation in rural properties defined by the Law of Protection of Native Vegetation was considered for the national level. Fifty-three protected areas were found in Pampa, with a total coverage of 3.23% of the biome Preservation mechanisms on rural properties have the potential to extend Pampa protected area system to up to 9.64%, but still depend on the environmental agencies validation. The percentage protected by protected areas in ecological systems ranged from zero to 17.76%, and nine of the 11 systems have less than 3% in protected areas. Data indicated that protected areas are relatively effective since 64% of them maintained or recovered their native vegetation cover. Data also indicated that protected area effectiveness has a relation to the dynamics in its surroundings regarding land use and vegetation cover. It is possible to affirm that Pampa protected areas are influenced by changes in land use in their vicinity. Protected areas must be managed considering these environmental influences to maintain their effectiveness. In perspective of expansion of the protected area system, the effort for conservation should be centered on the establishment of new protected areas with the diversification of management categories and in ecological systems with low percentages of protected areas cover. Data obtained here indicates that Pampa is unlikely to reach the 17% target in an ecologically representative protected area system by 2020.

As áreas protegidas são consideradas pilares para estratégias de conservação da diversidade biológica. Presume-se que a distribuição destas áreas representa a proteção de espécies e ecossistemas. Dentre as 20 metas globais para a redução da perda de biodiversidade, a Meta 11 de áreas protegidas estabelece, dentre outros aspectos, que 17% das áreas terrestres devem ser cobertas por sistemas de áreas protegidas ecologicamente representativos, efetivos, conectados e integrados a paisagens terrestres mais amplas. Neste estudo avaliou-se a representatividade ecológica, a efetividade e a integração a paisagens mais amplas do sistema de unidades de conservação, e perspectivas para subsidiar a sua ampliação no bioma Pampa. Além das unidades de conservação stricto senso, em parte das análises também foram considerados os sistemas complementares de terras indígenas e mecanismos de preservação em propriedades rurais definidos pela Lei de Proteção da Vegetação Nativa. A avaliação da representatividade foi feita considerando o Pampa (nível nacional) e também os 11 sistemas ecológicos presentes no bioma (nível regional). Foram levantadas 53 unidades de conservação no Pampa, com cobertura total de 3,23% do bioma Os mecanismos de preservação em propriedades rurais têm potencial de ampliar o sistema de áreas protegidas para até 9,64%, porém ainda depende de validação do órgão ambiental. O percentual protegido por unidades de conservação nos sistemas ecológicos variou entre 0% e 17,76%, sendo que nove dos 11 sistemas possuem menos de 3% em unidades de conservação. Os dados indicaram que as unidades são relativamente efetivas, pois 64% delas mantiveram ou recuperaram sua cobertura de vegetação nativa. As análises sugerem ainda, que a efetividade associada à cobertura vegetal no interior das unidades possui uma relação com a dinâmica no seu entorno. De forma geral, as unidades sofrem influência das alterações no uso da terra em suas adjacências. Para manutenção da efetividade da unidade de conservação, a unidade deve ser manejada considerando essas influências do entorno. Na perspectiva de ampliação do sistema, o esforço para conservação deve ser centrado na criação de novas unidades de conservação e diversificação de categorias. Os dados aqui obtidos indicam que o Pampa dificilmente alcançará a meta de 17% em um sistema de áreas protegidas ecologicamente representativo até 2020. / Protected areas are considered cornerstones for biodiversity conservation strategies. It is presumed that the distribution of these areas represents the protection of species and ecosystems. Among the 20 global targets for reducing biodiversity loss, Target 11 establishes that 17% of land areas must be covered by ecologically representative, effective and connected systems integrated to wider terrestrial landscapes, among other aspects. This study assessed ecological representativeness, effectiveness, and integration of protected area system, into wider landscapes of the Pampa biome. Perspectives to subsidize protected area expansion were also considered here. The representativeness assessment was made by considering the Pampa (national level) and also the 11 ecological systems present in the biome (regional level). Complementary systems of indigenous lands and mechanisms of preservation in rural properties defined by the Law of Protection of Native Vegetation was considered for the national level. Fifty-three protected areas were found in Pampa, with a total coverage of 3.23% of the biome Preservation mechanisms on rural properties have the potential to extend Pampa protected area system to up to 9.64%, but still depend on the environmental agencies validation. The percentage protected by protected areas in ecological systems ranged from zero to 17.76%, and nine of the 11 systems have less than 3% in protected areas. Data indicated that protected areas are relatively effective since 64% of them maintained or recovered their native vegetation cover. Data also indicated that protected area effectiveness has a relation to the dynamics in its surroundings regarding land use and vegetation cover. It is possible to affirm that Pampa protected areas are influenced by changes in land use in their vicinity. Protected areas must be managed considering these environmental influences to maintain their effectiveness. In perspective of expansion of the protected area system, the effort for conservation should be centered on the establishment of new protected areas with the diversification of management categories and in ecological systems with low percentages of protected areas cover. Data obtained here indicates that Pampa is unlikely to reach the 17% target in an ecologically representative protected area system by 2020.

One of the most important objectives for transportation engineers is to understand pavement surface properties and their positive and negative effects on the user. This can improve the design of the infrastructure, adequacy of tools, and consistency of methodologies that are essential for transportation practitioners regarding macrotexture characterization. Important pavement surface characteristics, or tire-pavement interactions, such as friction, tire-pavement noise, splash and spray, and rolling resistance, are significantly influenced by pavement macrotexture. This dissertation compares static and dynamic macrotexture measurements and proposes and enhanced method to quantify the macrotexture. Dynamic measurements performed with vehicle-mounted lasers have the advantage of measuring macrotexture at traffic speed. One drawback of these laser devices is the presence of 'spikes' in the collected data, which impact the texture measurements. The dissertation proposes two robust and innovative methods to overcome this limitation. The first method is a data-driven adaptive method that detects and removes the spikes from high-speed laser texture measurements. The method first calculates the discrete wavelet transform of the texture measurements. It then detects (at all levels) and removes the spikes from the obtained wavelet coefficients (or differences). Finally, it calculates the inverse discrete wavelet transform with the processed wavelet coefficients (without outliers) to obtain the Mean Profile Depth (MPD) from the measurements with the spikes removed. The method was validated by comparing the results with MPD measurements obtained with a Circular Texture Meter (CTMeter) that was chosen as the control device. Although this first method was able to successfully remove the spikes, it has the drawback that it depends on manual modeling of the distribution of the wavelet coefficients to correctly define an appropriate threshold. The next step of this dissertation proposes an enhanced to the spike removal methodology for macrotexture measurements taken with high-speed laser devices. This denoising methodology uses an algorithm that defines the distribution of texture measurements by using the family of Generalized Gaussian Distributions (GGD), along with the False Discovery Rate (FDR) method that controls the proportion of wrongly identified spikes among all identified spikes. The FDR control allows for an adaptive threshold selection that differentiates between valid measurements and spikes. The validation of the method showed that the MPD results obtained with denoised dynamic measurements are comparable to MPD results from the control devices. This second method is included as a crucial step in the last stage of this dissertation as explained following. The last part of the dissertation presents an enhanced macrotexture characterization index based on the Effective Area for Water Evacuation (EAWE), which: (1) Estimates the potential of the pavement to drain water and (2) Correlates better with two pavement surface properties affected by macrotexture (friction and noise) that the current MPD method. The proposed index is defined by a three-step process that: (1) removes the spikes, assuring the reliability of the texture profile data, (2) finds the enveloping profile that is necessary to delimit the area between the tire and the pavement when contact occurs, and (3) computes the EAWE. Comparisons of current (MPD) and proposed (EAWE) macrotexture characterization indices showed that the MPD overestimates the ability of the pavement for draining the surface water under a tire. / Ph. D.