The NASA Scientific and Technical Information Program: Exploring challenges, creating opportunities

The NASA Scientific and Technical Information (STI) Program offers researchers access to the world's largest collection of aerospace information. An overview of Program activities, products and services, and new directions is presented. The R&D information cycle is outlined and specific examples of the NASA STI Program in practice are given. Domestic and international operations and technology transfer activities are reviewed and an agenda for the STI Program NASA-wide is presented. Finally, the incorporation of Total Quality Management and evaluation metrics into the STI Program is discussed

Outburst evolution, historic light curve and a flash-ionized nebula around the WZ Sge-type object PNV J03093063+2638031

We have monitored the 2014 superoutburst of the WZ Sge-type transient PNV J03093063+2638031 for more than four months, from V=11.0 maximum brightness down to V=18.4 mag, close to quiescence value, by obtaining BVRI photometry and low resolution fluxed spectroscopy. The evolution was normal and no late-time `echo' outbursts were observed. The absolute integrated flux of emission lines kept declining along the superoutburst, and their increasing contrast with the underlying continuum was simply the result of the faster decline of the continuum compared to the emission lines. Inspection of historical Harvard plates covering the 1899-1981 period did not reveal previous outbursts, neither `normal' nor 'super'. We discovered an extended emission nebula (radius ~1 arcmin) around PNV J03093063+2638031, that became visible for a few months as the result of photo-ionization from the superoutburst of the central star. It is not present on Palomar I and II sky survey images and it quickly disappeared when the outburst was over. From the rate at wich the inization front swept through the nebula, we derive a distance of ~120 pc to the system. The nebula is density bounded with an outer radius of 0.03 pc, and the absolute magnitude of the central star in quiescence is M(V)~14.2 mag. The electron density in the nebula is estimated to be 10(+5) cm(-3) from the observed recombination time scale. Given the considerable substructures seen across the nebula, a low filling factor is inferred. Similar nebulae have not been reported for other WZ Sge objects and the challenges posed to models are considered.Comment: Astronomy & Astrophysic

The Effects of Elasticity in the Foundation on the Flutter of a Metallic High Aspect Ratio Wing

The goal of this thesis is to study the flutter characteristics of a metallic high-aspect ratio wing, with linearly varying chord across the semis-span, and a simulated elastic foundation. The general planform of the wing is similar to the one found in a High- Altitude Long-Endurance Uninhabited Aerial Surveillance Vehicle (HALE USAV). The problem is studied using a simplified aerodynamic loading based on thin-airfoil theory, which is then combined with a Lagrangian formulation to solve the system as stationary. The wing has no control surfaces or external stores, and is modeled as a uniform beam with known mechanical properties, being attached to a combination of torsion springs at the root to reproduce the elastic foundation. The analysis of the problem includes the development of a Matlab code, which permits different root conditions to be defined, and computes the flutter speed and frequency, outputting information in the form of plots and data lists, making the analysis easy to follow

An automatic classification and robust segmentation procedure of spatial objects

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Minimally invasive Port-Access repair of a left ventricular pseudoaneurysm

AbstractJ Thorac Cardiovasc Surg 2002;124:1242-

Assessment of forestry parameters at single-tree level by using methods of LIDAR data analysis and processingAvaliação de parâmetros florestais de árvores individuais utilizando métodos de análise e processamento de dados LIDAR

AbstractIn this paper a chain of laser scanning data processing in order to automatically detect the principal forestry parameters deriving from a single-tree extraction approach is presented. The overall method was based on mathematical morphology operations to assess the cartographical position of them, as well as the height of the trees. Starting from single-extracted trees, a segmentation algorithm made it possible to classify the laser point data as a subset of crown points. For each tree, some morphometric and biometric parameters were estimated. A method to distinguish between some of principal tree species of alpine latitudes is afterwards presented. The species classification was based on the study of the single crown Gaussian curvature, from estimated differential parameters of the Taylor’s formula extended to second order terms. The experiments, carried out in the Alpine context of the North-East Italy (Friuli Venezia Giulia Region), highlighted that the percentage of tree extraction ranged between 70% and 95% in juvenile and mature forests respectively while 80% - 90% of corrected classified tree species (coniferous and broad-leaved) was obtained. Concerning the stand volume, the estimation accuracy varied between 80% and 95% in broad-leaved and coniferous stands respectively. ResumoNeste trabalho, é apresentado uma cadeia de processamento de dados de rastreamento a laser, a fim de detectar automaticamente os parâmetros florestais  principais decorrentes de uma abordagem de extração de árvores individuais. O método global foi baseado em operações de morfologia matemática para avaliar a posição cartográfica, bem como a altura das árvores. A partir da extração de árvores individuais, um algoritmo de segmentação permitiu classificar os dados a laser como um subconjunto de pontos de copas. Para cada árvore, alguns parâmetros morfométricos e biométricos foram estimados. Um método para distinguir algumas das principais espécies de árvores de altitudes alpinas é apresentado depois. A classificação de espécie foi baseada em estudos da curvatura de Gaussian de árvores de copa única, de parâmetros diferenciais estimados pela fórmula de Taylor estendidos aos termos de segunda ordem. Os experimentos, realizados no nordeste da Itália (região de Friul-Veneza Júlia), destacou que o percentual de extração de árvore variou entre 70% e 95% em florestas juvenil e adulta respectivamente, enquanto 80% - 90% das espécies de árvores classificadas (coníferas e folhosas) foram obtidas. Quanto ao volume de povoamento, a precisão da estimativa variou entre 80% e 95% em povoamento de folhosas e coníferas, respectivamente

From a diameter-based to a height-based dendrometry: estimate of tree volume from laser scanning measurements

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