Modélisation procédurale par composants

Le réalisme des images en infographie exige de créer des objets (ou des scènes) de plus en plus complexes, ce qui entraîne des coûts considérables. La modélisation procédurale peut aider à automatiser le processus de création, à simplifier le processus de modification ou à générer de multiples variantes d'une instance d'objet. Cependant même si plusieurs méthodes procédurales existent, aucune méthode unique permet de créer tous les types d'objets complexes, dont en particulier un édifice complet. Les travaux réalisés dans le cadre de cette thèse proposent deux solutions au problème de la modélisation procédurale: une solution au niveau de la géométrie de base, et l’autre sous forme d'un système général adapté à la modélisation des objets complexes. Premièrement, nous présentons le bloc, une nouvelle primitive de modélisation simple et générale, basée sur une forme cubique généralisée. Les blocs sont disposés et connectés entre eux pour constituer la forme de base des objets, à partir de laquelle est extrait un maillage de contrôle pouvant produire des arêtes lisses et vives. La nature volumétrique des blocs permet une spécification simple de la topologie, ainsi que le support des opérations de CSG entre les blocs. La paramétrisation de la surface, héritée des faces des blocs, fournit un soutien pour les textures et les fonctions de déplacements afin d'appliquer des détails de surface. Une variété d'exemples illustrent la généralité des blocs dans des contextes de modélisation à la fois interactive et procédurale. Deuxièmement, nous présentons un nouveau système de modélisation procédurale qui unifie diverses techniques dans un cadre commun. Notre système repose sur le concept de composants pour définir spatialement et sémantiquement divers éléments. À travers une série de déclarations successives exécutées sur un sous-ensemble de composants obtenus à l'aide de requêtes, nous créons un arbre de composants définissant ultimement un objet dont la géométrie est générée à l'aide des blocs. Nous avons appliqué notre concept de modélisation par composants à la génération d'édifices complets, avec intérieurs et extérieurs cohérents. Ce nouveau système s'avère général et bien adapté pour le partionnement des espaces, l'insertion d'ouvertures (portes et fenêtres), l'intégration d'escaliers, la décoration de façades et de murs, l'agencement de meubles, et diverses autres opérations nécessaires lors de la construction d'un édifice complet.

Carta de Aptidão para a implantação de rodovias e avaliação de alternativas de traçado com uso de geotecnologias

This study discuss the use of the geotechnologies to aid the planners on the terrain aptness definition for highways implantation and on the different trace evaluation to the extention of the Governador Carvalho Pinto highway, between Taubaté-SP and Aparecida do Norte-SP. Fratures on the area were mapping using Landsat ETM+, band Pan. In order to elaborate the phisical aptness chart for highway implantation was used the Analitical Hierarchy Process (AHP) operation, in on geographical information system (GIS). Using GIS were realized a ponderate middle with the soils, rocks, relief, slope, fractures and land use/cover maps. Using this physical aptness chart and joinning it with urban and restrict areas (that was inserted by the Boolean operation), were obtained a viability chart for highway implantation. Based on it were proposed three aleatory traces for the Carvalho Pinto highway. This traces were evaluated with the cross tabulation operation. The integration of the restrict areas, land use and phisical aptness in digital media can offer for the planners the cartography of the viability for the highway implantation. The evaliation of these three traces, based on the viability chart, can subsidyse the decision by the planners.

Boolean logic device done with DFB laser diode

We present simulation results on how power output-input characteristic Instability in Distributed FeedBack -DFB semiconductor laser diode SLA can be employed to implemented Boolean logic device. Two configurations of DFB Laser diode under external optical injection, either in the transmission or in the reflective mode of operation, is used to implement different Optical Logic Cells (OLCs), called the Q- and the P-Device OLCs. The external optical injection correspond to two inputs data plus a cw control signal that allows to choose the Boolean logic function to be implement. DFB laser diode parameters are choosing to obtain an output-input characteristic with the values desired. The desired values are mainly the on-off contrast and switching power, conforming shape of hysteretic cycle. Two DFB lasers in cascade, one working in transmission operation and the other one in reflective operation, allows designing an inputoutput characteristic based on the same respond of a self-electrooptic effect device is obtained. Input power for a bit'T' is 35 uW(70uW) and a bit "0" is zero for all the Boolean function to be execute. Device control signal range to choose the logic function is 0-140 uW (280 uW). Q-device (P-device)

48.8 km Ultralong Erbium fiber laser in active mode-locking operation

By the use of installed fibers inside the city we demonstrated a 48.8 km ultralong Erbium-doped fiber laser in modelocking regime with repetition rate varying from 1-10 GHz. The shortest pulse duration of 42 ps at 2.5 GHz was obtained by optimization of intracavity dispersion.

Effect of impeller type and mechanical agitation on the mass transfer and power consumption aspects of ASBR operation treating synthetic wastewater

The effect of flow type and rotor speed was investigated in a round-bottom reactor with 5 L useful volume containing 2.0 L of granular biomass. The reactor treated 2.0 L of synthetic wastewater with a concentration of 800 mgCOD/L in 8-h cycles at 30 degrees C. Five impellers, commonly used in biological processes, have been employed to this end, namely: a turbine and a paddle impeller with six-vertical-flat-blades, a turbine and a paddle impeller with six-45 degrees-inclined-flat-blades and a three-blade-helix impeller. Results showed that altering impeller type and rotor speed did not significantly affect system stability and performance. Average organic matter removal efficiency was about 84% for filtered samples, total volatile acids concentration was below 20 mgHAc/L and bicarbonate alkalinity a little less than 400 mgCaCO(3)/L for most of the investigated conditions. However, analysis of the first-order kinetic model constants showed that alteration in rotor speed resulted in an increase in the values of the kinetic constants (for instance, from 0.57 h(-1) at 50 rpm to 0.84 h(-1) at 75 rpm when the paddle impeller with six-45 degrees-inclined-flat-blades was used) and that axial flow in mechanically stirred reactors is preferable over radial-flow when the vertical-flat-blade impeller is compared to the inclined-flat-blade impeller (for instance at 75 rpm, from 0.52 h(-1) with the six-flat-blade-paddle impeller to 0.84 h(-1) with the six-45 degrees-inclined-flat-blade-paddle impeller), demonstrating that there is a rotor speed and an impeller type that maximize solid-liquid mass transfer in the reaction medium. Furthermore, power consumption studies in this reduced reactor volume showed that no high power transfer is required to improve mass transfer (less than 0.6 kW/10(3) m(3)). (C) 2008 Elsevier Ltd. All rights reserved.

Planning and operation of large-scale water distribution systems with preemptive priorities

This paper describes the development of an optimization model for the management and operation of a large-scale, multireservoir water supply distribution system with preemptive priorities. The model considers multiobjectives and hedging rules. During periods of drought, when water supply is insufficient to meet the planned demand, appropriate rationing factors are applied to reduce water supply. In this paper, a water distribution system is formulated as a network and solved by the GAMS modeling system for mathematical programming and optimization. A user-friendly interface is developed to facilitate the manipulation of data and to generate graphs and tables for decision makers. The optimization model and its interface form a decision support system (DSS), which can be used to configure a water distribution system to facilitate capacity expansion and reliability studies. Several examples are presented to demonstrate the utility and versatility of the developed DSS under different supply and demand scenarios, including applications to one of the largest water supply systems in the world, the Sao Paulo Metropolitan Area Water Supply Distribution System in Brazil.

A systemic approach for optimal cooling tower operation

The thermal performance of a cooling tower and its cooling water system is critical for industrial plants, and small deviations from the design conditions may cause severe instability in the operation and economics of the process. External disturbances such as variation in the thermal demand of the process or oscillations in atmospheric conditions may be suppressed in multiple ways. Nevertheless, such alternatives are hardly ever implemented in the industrial operation due to the poor coordination between the utility and process sectors. The complexity of the operation increases because of the strong interaction among the process variables. In the present work, an integrated model for the minimization of the operating costs of a cooling water system is developed. The system is composed of a cooling tower as well as a network of heat exchangers. After the model is verified, several cases are studied with the objective of determining the optimal operation. It is observed that the most important operational resources to mitigate disturbances in the thermal demand of the process are, in this order: the increase in recycle water flow rate, the increase in air flow rate and finally the forced removal of a portion of the water flow rate that enters the cooling tower with the corresponding make-up flow rate. (C) 2009 Elsevier Ltd. All rights reserved.

Cryogenic operation of FinFETs aiming at analog applications

FinFETs are recognized as promising candidates for the CMOS nanometer era. In this paper the most recent results for cryogenic operation of FinFETs will be demonstrated with special emphasis on analog applications. Threshold voltage, subthreshold slope and carrier mobility will be studied. Also some important figures of merit for analog circuit operation as for readout electronics, such as transconductance, output conductance and intrinsic voltage gain will be covered. It is demonstrated that the threshold voltage of undoped narrow FinFETs is less temperature-dependent than for a planar single-gate device with similar doping concentration. The temperature reduction improves the transconductance over drain current ratio in any operational region. On the other hand, the output conductance is degraded when the temperature is reduced. The combination of these effects shows that the intrinsic gain of a L = 90 nm FinFET is degraded by 2 dB when the temperature reduces from 300 K to 100 K. (C) 2009 Elsevier Ltd. All rights reserved.

Influence of the sidewall crystal orientation, HfSiO nitridation and TiN metal gate thickness on n-MuGFETs under analog operation

This work characterizes the analog performance of SOI n-MuGFETs with HfSiO gate dielectric and TiN metal gate with respect to the influence of the high-k post-nitridation. TiN thickness and device rotation. A thinner TiN metal gate is found favorable for improved analog characteristics showing an increase in intrinsic voltage gain. The devices where the high-k material is subjected to a nitridation step indicated a degradation of the Early voltage (V(EA)) values which resulted in a lower voltage gain. The 45 degrees rotated devices have a smaller V(EA) than the standard ones when a HfSiO dielectric is used. However, the higher transconductance of these devices, due to the increased mobility in the (1 0 0) sidewall orientation, compensates this V(EA) degradation of the voltage gain, keeping it nearly equal to the voltage gain values of the standard devices. (C) 2011 Elsevier Ltd. All rights reserved.

Cryogenic Operation of Junctionless Nanowire Transistors

This letter presents the properties of nMOS junctionless nanowire transistors (JNTs) under cryogenic operation. Experimental results of drain current, subthreshold slope, maximum transconductance at low electric field, and threshold voltage, as well as its variation with temperature, are presented. Unlike in classical devices, the drain current of JNTs decreases when temperature is lowered, although the maximum transconductance increases when the temperature is lowered down to 125 K. An analytical model for the threshold voltage is proposed to explain the influence of nanowire width and doping concentration on its variation with temperature. It is shown that the wider the nanowire or the lower the doping concentration, the higher the threshold voltage variation with temperature.

Water Treatment Plant Sludge Discharge to Wastewater Treatment Works: Effects on the Operation of Upflow Anaerobic Sludge Blanket Reactor and Activated Sludge Systems

This experiment examined the effects of the discharge of water treatment plant (WTP) sludge into the following three types of wastewater treatment systems: a pilot-scale upflow anaerobic sludge blanket (UASB) reactor, a pilot-scale activated sludge system, and a full-scale activated sludge sequencing batch reactor (SBR). The UASB reactor received 50 mg of suspended solids ( SS) of WTP sludge per liter of wastewater in the first phase, and, in the second phase, it received 75 mg SS/L. The pilot-scale activated sludge system received 25 and 50 mg SS/L in the first and second phases, respectively. The full-scale WWTP ( SBR) received approximately 74 mg SS/L. The results of the experiments showed that, despite some negative effects on nitrification, there were positive effects on phosphorus removal, and, furthermore, there was the addition of solids in all systems. Water Environ. Res., 82, 392 ( 2010).

Thermodynamic information system for diagnosis and prognosis of power plant operation condition

A thermodynamic information system for diagnosis and prognosis of an existing power plant was developed. The system is based on an analytic approach that informs the current thermodynamic condition of all cycle components, as well as the improvement that can be obtained in the cycle performance by the elimination of the discovered anomalies. The effects induced by components anomalies and repairs in other components efficiency, which have proven to be one of the main drawbacks in the diagnosis and prognosis analyses, are taken into consideration owing to the use of performance curves and corrected performance curves together with the thermodynamic data collected from the distributed control system. The approach used to develop the system is explained, the system implementation in a real gas turbine cogeneration combined cycle is described and the results are discussed. (C) 2011 Elsevier Ltd. All rights reserved.

Iliac-hepatic arterial bypass for compromised collateral flow during modified Appleby operation for advanced pancreatic cancer

Involvement of the celiac trunk and common hepatic artery are two of the most common forms of vascular invasion by tumours of the distal pancreas, and until recently this finding was considered a contra-indication to resection. We described a modified Appleby operation for locally advanced distal pancreatic cancer with compromised hepatic collateral flow that needed hepatic arterial revascularization, successfully accomplished by left external iliac-hepatic arterial bypass with Dacron prosthesis. Patient recovery was uneventful and he was discharged on the 10th postoperative day. Postoperative angio-CT disclosed a patent arterial bypass. Patient is well and asymptomatic 13 months after operation. At the time of this writing, postoperative CT scan showed no evidence of disease and CA 19-9 level is normal. There is a well established rationale to perform extended resection of pancreatic carcinomas that compromise vascular structures. Modified Appleby procedure can safely be performed, has oncological advantages to palliative procedures and provides relief of pain but is reserved for selected patients. Preservation of hepatic arterial flow has utmost importance to avoid hepatobiliary complications as liver necrosis, liver abscess, gallbladder necrosis or cholecystitis. In this case, hepatic revascularization was particularly challenging, but was successfully accomplished by left external iliac-hepatic arterial bypass. To our knowledge this type of arterial bypass has never been described so far in the English literature and its description may be important for surgeons dealing with advanced pancreatic cancer. (C) 2009 Elsevier Ltd. All rights reserved.