No description available.

No description available.

No description available.

No description available.

The Eppley Precision Spectral Pyranometer (PSP) is a shortwave radiometer that is widely used in global networks to monitor solar irradiances at the earth's surface. Within the instrument, a blackened surface is in intimate thermal contact with the hot junction of a thermopile. The cold junction of the thermopile communicates thermally with the large thermal capacitance of the instrument body, which acts as a heat sink. Radiation arrives at the blackened surface through one or two hemispherical dome-shaped filters that limit the instrument response to the solar spectrum. The voltage developed by the thermopile is then interpreted in terms of the incident irradiance. Measurements taken with the pyranometer are compared with results from theoretical models. Discrepancies between model results and measurements are used to isolate inaccuracies in the optical properties of the atmosphere used in the models. As the accuracy of the models increases, the reliability of the measurements must be examined in order to assure that the models keep up with reality. The sources of error in the pyranometer are examined in order to determine the accuracy of the instrument. Measurements obtained using the pyranometer are known to be influenced by environmental conditions such as ambient temperature, wind, and cloud cover [Bush, et al., 1998]. It is surmised that at least some of the observed environmental variability in these data is due to parasitic thermal exchanges within the instrument [Haeffelin et al., 1999]. Thermal radiation absorbed and emitted by the filters, as well as that reflected and re-reflected among the internal surfaces, influences the net radiation at the detector surface and produces an offset from the signal that would result from the incident shortwave radiation alone. Described is an ongoing effort to model these exchanges and to use experimental results to verify the model. The ultimate goal of the work described is to provide reliable protocols, based on an appropriate instrument model, for correcting measured shortwave irradiance for a variable thermal radiation environment. / Master of Science

Carbon is a metric at the centre of contemporary debates. It is invoked to explain responses to climate change and justify political decisions over the economy and environment. Its ubiquity might suggest that the definition of carbon is broadly agreed upon, but along with greenhouse gas (GHG) measurements, articulating carbon as a commodity has incorporated debates over sustainable development (SD). The use of market-based mechanisms to manage carbon quantities results in articulations of the concept that reinforce consumption as a means to achieve public policy aims, but these are also contested. This research examines the concept of carbon to explore what might be taken-for-granted or overlooked when carbon is invoked. The research takes an ethnographic approach to carbon by examining offsetting – paying for reductions in GHG emissions at one location to make up for a continuation or increase of emissions at another. The novelty, complexity and lack of trust in carbon offsetting have resulted in numerous voluntary standards to improve consumer confidence in this commodity. The standard organisations’ position in codifying, measuring and accrediting carbon makes them valuable sites at which to describe the materialities of the concept. I use data collected from the administrative offices of two voluntary carbon offset standards in 2010-11 to explore what is included and excluded within carbon as it was enacted at these sites. Carbon is described in this research as an assemblage and a multiplicity – it is articulated in varying ways by actors within offset markets. Through the work of standards organisations, the “orthodoxies” of offsetting are identified as taken-for-granted features of carbon. In contrast, the position of SD is identified as variable across different articulations of carbon. Using a post-Actor Network Theory approach innovatively combined with Suchman’s typology of legitimacy, this diversity in carbon is not normatively evaluated; instead the focus is on how assemblages of carbon differentiate the legitimacy of SD as a feature of offsetting. Some take SD for granted as an inherent aspect of offsetting, for others it is a desirable feature, but not necessary. Alternatively it could be offered as an add-on possibility without suggesting SD implied better offsetting, and for others offsetting was best enacted without assembling SD concerns. Exploring carbon as an assemblage demonstrates the continuous and flexible constructions of carbon as a commodity and concept. When examined in detail, the marketing strategies and technical rules of different standards produce varying articulations of carbon. Furthermore, this research explores how the work of voluntary carbon offset standards excludes the scrutiny of sites of consumption of offsets. This exclusion, as with the integration of SD, is notable for the differences in how it is articulated by standard staff – challenged by some, taken-for-granted by others but with diverse rationales for each position. These features are informative in relation to the roles ascribed to voluntary standards across other commodities as well as in relation to carbon. Attending to the multiplicity that exists in the daily practices of offset markets suggests possibilities for those looking to stabilise or reform the concept of carbon as well as understanding the activities of voluntary standards.

Les modifications physiologiques dans la configuration spatiale des organes pelviens sont de plus en plus diagnostiquées et traitées pour améliorer la qualité de vie des patientes. Le projet MoDyPe (ANR-09-SYSC-008) a été créé pour concevoir un simulateur chirurgical patiente-spécifique, et quantifier le geste médical en mode pré-opératoire. La modélisation géométrique des organes se fait à partir de nuages de points épars bruités. Les formes sont considérées fermées, lisses, creuses et à membrane épaisse. Le processus est décomposé en deux étapes : la construction de la surface et l'ajout d'une épaisseur.Afin de respecter les contraintes physiologiques, de manipuler la géométrie et de localiser précisément un point sur la surface, une B-spline de genre 0 au moins C1-continue est ajustée aux données. La fonction à minimiser est basée sur une énergie bidirectionnelle, caractérisant la dissimilarité des données sur l'échantillonnage et inversement. Sa réduction repose sur un schéma alternant re-paramétrisation et descente de gradient à pas optimal.Une surface-offset est ensuite générée vers l'intérieur de l'organe, via un maillage discret, en traitant le problème d'auto-intersection. Elle exploite la forme allongée des organes, grâce à un axe curviligne décrivant leur diamètre généralisé.Finalement, un maillage hexaédrique est créé à partir de la surface ajustée et de l'offset, qui sert à la simulation mécanique du comportement des organes à l'étape suivante du projet. / Physiological changes in the spatial configuration of the organs in the pelvic area are increasingly taken into account and treated to enhance the comfort of patients. MoDyPe project (ANR-09-SYSC-008 french support) has been created to develop a patient-specific simulator and to quantify the surgical gesture for preoperative purposes. The geometric modeling of the organs starts with noisy scattered point clouds. The shapes have been considered closed, smooth, hollow with a thick membrane. The process can be divided into two main parts: the construction of the surface and the addition of a thickness.In order to meet the physiological constraints, to manipulate the geometry and to accurately localize a point on the surface, a 0-genus B-spline surface is fitted to the data. It minimizes a bidirectional energy, characterizing the dissimilarities between the surface sampling and the input dataset. Its reduction is based on an alternate scheme between re-parametrization and optimal steepest descent step.Once achieved, an offset-surface is generated inwards, helped by a mesh to overcome self-intersection problems. The method created takes into account the elongated shapes of the organs, based on a curvilinear axis describing their generalized diameter.Finally, a hexahedral mesh is created from the fitted surface and its offset. It is the start point for the next step of the project consisting in mechanically simulating the dynamic behavior of the organs.

This thesis proposes a blind receiver for the Nyquist pulse shaped quadratureamplitude modulation (QAM) signals. The focus is on single carrier signals. The blind receiver includes the estimation of the symbol rate, the roll-off factor of the filter, the optimal sample phase, the frequency offset, the phase offset and as well as the correction of frequency and phase offsets. The blind receiver is proposed for the cognitive radio applications. Cognitive radios are intelligent devices which can adapt themselves according to its user and its environment, i.e. they are aware of the user and the environment. Another importance of cognitive radios is they can detect the incoming signal and demodulate it and also respond to the transmitting node with the same parameters. In order to demodulate the signal and to respond the transmitter node, there are some parameters which are needed to be known. The estimation starts with the bandwidth and carrier frequency, continued by the estimation of the symbol rate, which is a crucial factor. After the estimation and restrictions of these parameters, the roll-off factor of the filter is estimated for match filtering to remove the inter symbol interference (ISI) effect. Then the optimal sample phase is detected and the signal is downsampled. The following procedures include the modulation identification and estimation and correction of both frequency and phase offsets. The estimation algorithms performance is compared to the performances of the other algorithms available in the literature. These simulation results are presented and discussed in this thesis.

The Surface Deformation Prediction System (SDPS) program has been developed as an engineering tool for the prediction of subsidence deformation indices through the implementation of an influence function. SDPS provides reliable predictions of mining induced surface displacements, strains, and tilt for varying surface topography. One of the key aspects in obtaining reliable ground deformation prediction is the determination of the edge effect offset. The value assigned to the edge effect corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined out area. The objective of this thesis is to describe the methods implemented in updating the edge effect offset algorithm within SDPS. Using known geometric equations, the newly developed algorithm provides a more robust calculation of the offset boundary line of the extracted panel for simplistic and complex mining geometries. Assuming that an extracted panel is represented by a closed polyline, the new edge offset algorithm calculates a polyline offset into the extracted panel by the user defined edge effect offset distance. Surface deformations are then calculated using this adjusted panel geometry. The MATLAB® program was utilized for development and testing of the new edge effect offset feature.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / A single-tone frequency estimator for a non-uniformly sampled sinusoid is proposed. A nonuniformly sampled sinusoid may be generated from the received training sequences of a telemetry link. The frequency of the sinusoid matches the carrier-frequency-offset (CFO) of the received signal, and estimation of this quantity allows a receiver to compensate for the CFO. The performance bounds of this type of estimator have been investigated in the literature, though little work has been published on practical algorithms. The estimator proposed in this paper is a generalization of phase-increment estimators previously described in the literature. It exhibits a low computational complexity yet converges to theoretical bounds at high SNR. The paper argues that a periodic training sequence structure, combined with the new estimator, allows for a high-accuracy and lowcomplexity CFO compensator.