125 research outputs found
Orientation computation of an inclined textured plane: accuracy and performances
The aim of this paper is to present one method for computing the orientation of an inclined textured plane with
only one view of this plane. Two steps are used for this computation. First we build a local scales map by a wavelets
decomposition of the image of the plane. Then we have to do an interpolation of this map by use the theoretical
equation of the local scales variation. So we obtain features values which allow us to compute the tilt and the
slant angles. After developing the computation technique, we do a theoretical study in order to know the precision
of the method. For the tilt angle, the precision is about one degree, but for the slant angle the precision is
only about five degrees, if the slant angle is over forty degrees. But, we have to know the camera parameters for
computing the slant angle. If there is some errors about these parameters, so the slant angle will be bad. After this study, we build a data base of one hundred images of real textures with different tilt and slant angles. The camera
which has been used for acquiring the images has been calibrated. Results on this data base are agree with the
theoretical study.Le but de cet article est de présenter une méthode de calcul de l'orientation d'un plan texturé incliné à partir d'une seule vue de ce plan. Cette méthode est constituée de deux étapes. Dans un premier temps on calcule, à partir de l'image initiale, une carte des échelles locales. Ces échelles sont obtenues au moyen d'une décomposition en ondelettes de l'image d'origine. Puis on interpole cette carte des échelles locales par l'équation théorique de leurs variations. On obtient ainsi des paramètres qui permettent de calculer les angles de tilt et de slant, décrivant l'orientation du plan. Pour valider cette démarche, nous avons mené une étude théorique sur la précision qui pouvait être atteinte par une telle méthode. Nous avons pu mettre en évidence que, si la précision sur l'angle de tilt était assez bonne (de l'ordre de 1°), celle sur l'angle de slant n'excédait pas 5°, à condition que cet angle soit suffisamment important (supérieur à 40°). Mais la précision sur l'angle de slant est conditionnée par la connaissance des paramètres de prise de vue. En effet, nous avons mis en évidence que l'utilisation de valeurs erronées des paramètres de la caméra entraînerait une erreur maximum pour un slant entre 40° et 50°, c'est à dire, a priori, là où la méthode est la meilleure. Cette étude théorique a été validée par des expérimentations sur des images de synthèse et sur des images de textures réelles. Une base de données d'une centaine d'images a été constituée, au moyen d'une caméra préalablement calibrée, pour évaluer la qualité des résultats fournis par notre méthode
Compendium of Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA
Vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear, and hybrid devices
Compendium of Current Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA
Total ionizing dose and displacement damage testing is performed to characterize and determine the feasibility of candidate electronics for NASA spacecraft and program use. AEROSPACE ENVIRONMENT
Compendium of Current Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA
Total ionizing dose and displacement damage testing is performed to characterize and determine the suitability of candidate electronics for NASA spacecraft and program use
Recent Total Ionizing Dose and Displacement Damage Compendium of Candidate Electronics for NASA Space Systems
Vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices
Compendium of Single Event Effects, Total Ionizing Dose, and Displacement Damage for Candidate Spacecraft Electronics for NASA
We present results and analysis investigating the effects of radiation on a variety of candidate spacecraft electronics to proton and heavy ion-induced single-event effects (SEE), proton-induced displacement damage (DD), and total ionizing dose (TID). This paper is a summary of test results
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SEIS: Insight's Seismic Experiment for Internal Structure of Mars.
By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars' surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking's Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars' surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of M w ∼ 3 at 40 ∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution.Electronic supplementary materialThe online version of this article (10.1007/s11214-018-0574-6) contains supplementary material, which is available to authorized users
Proteomics: in pursuit of effective traumatic brain injury therapeutics
Effective traumatic brain injury (TBI) therapeutics remain stubbornly elusive. Efforts in the field have been challenged by the heterogeneity of clinical TBI, with greater complexity among underlying molecular phenotypes than initially conceived. Future research must confront the multitude of factors comprising this heterogeneity, representing a big data challenge befitting the coming informatics age. Proteomics is poised to serve a central role in prescriptive therapeutic development, as it offers an efficient endpoint within which to assess post-TBI biochemistry. We examine rationale for multifactor TBI proteomic studies and the particular importance of temporal profiling in defining biochemical sequences and guiding therapeutic development. Lastly, we offer perspective on repurposing biofluid proteomics to develop theragnostic assays with which to prescribe, monitor and assess pharmaceutics for improved translation and outcome for TBI patients
Comprehensive Essentiality Analysis of the Mycobacterium tuberculosis Genome via Saturating Transposon Mutagenesis
For decades, identifying the regions of a bacterial chromosome that are necessary for viability has relied on mapping integration sites in libraries of random transposon mutants to find loci that are unable to sustain insertion. To date, these studies have analyzed subsaturated libraries, necessitating the application of statistical methods to estimate the likelihood that a gap in transposon coverage is the result of biological selection and not the stochasticity of insertion. As a result, the essentiality of many genomic features, particularly small ones, could not be reliably assessed. We sought to overcome this limitation by creating a completely saturated transposon library in Mycobacterium tuberculosis. In assessing the composition of this highly saturated library by deep sequencing, we discovered that a previously unknown sequence bias of the Himar1 element rendered approximately 9% of potential TA dinucleotide insertion sites less permissible for insertion. We used a hidden Markov model of essentiality that accounted for this unanticipated bias, allowing us to confidently evaluate the essentiality of features that contained as few as 2 TA sites, including open reading frames (ORF), experimentally identified noncoding RNAs, methylation sites, and promoters. In addition, several essential regions that did not correspond to known features were identified, suggesting uncharacterized functions that are necessary for growth. This work provides an authoritative catalog of essential regions of the M. tuberculosis genome and a statistical framework for applying saturating mutagenesis to other bacteria
Ethnic-Racial Socialization in Early Childhood: The Implications of Color-Consciousness and Colorblindness for Prejudice Development
This chapter outlines how early childhood teachers can bring children into conversations surrounding race and racism by drawing on literature on how parents of color discuss these topics. Although educators’ practices surrounding race and racism remain largely unexplored, decades of developmental psychological research indicate that parents of color engage in ethnic-racial socialization practices that are beneficial for children (Hughes et al., 2006). The established dimensions of parental ethnic-racial socialization include (1) cultural socialization, or teaching children about their ethnic heritage and instilling ethnic pride; (2) preparation for bias, or teaching children about racism and preparing them to face discrimination; (3) promotion of mistrust, or warning children about the need to distance themselves from other racial groups; and (4) egalitarianism, or emphasizing the similarities between and equality of all races (Hughes et al. 2006). One consideration to take into account from a developmental perspective is that children’s level of cognitive development impacts how they interpret messages about race. This chapter draws a link between parental ethnic-racial socialization and extends this body of work to school settings, with a focus on teachers. The ideologies of colorblindness and color-consciousness are discussed throughout
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