33 research outputs found
SURAT PENCATATAN CIPTAAN Karya Rekaman: Inovasi Pengajaran Gerak Dasar Tari Bali Dengan Bahasa Inggris Dalam Upaya Memperkokoh Kiprah ISI Denpasar di Dunia Internasional
Spatial joins are join operations that involve spatial data types and operators. Spatial access methods are often used to speed up the computation of spatial joins. This paper addresses the issue of benchmarking spatial join operations. For this purpose, we first present a WWW-based benchmark generator to produce sets of rectangles. Using a Web browser, experimenters can specify the number of rectangles in a sample, as well as the statistical distributions of their sizes, shapes, and locations. Second, using the generator and a well-defined set of statistical models we define several tests to compare the performance of three spatial join algorithms: nested loop, scan-and-index, and synchronized tree traversal. We also added a real-life data set from the Sequoia 2000 storage benchmark. Our results show that the relative performance of the different techniques mainly depends on two parameters: sample size, and selectivity of the join predicate. All of the statistical models and algorithms are available on the Web, which allows for easy verification and modification of our experiments.Peer Reviewe
FIREBall-2: advancing TRL while doing proof-of-concept astrophysics on a suborbital platform
Here we discuss advances in UV technology over the last decade, with an
emphasis on photon counting, low noise, high efficiency detectors in
sub-orbital programs. We focus on the use of innovative UV detectors in a NASA
astrophysics balloon telescope, FIREBall-2, which successfully flew in the Fall
of 2018. The FIREBall-2 telescope is designed to make observations of distant
galaxies to understand more about how they evolve by looking for diffuse
hydrogen in the galactic halo. The payload utilizes a 1.0-meter class telescope
with an ultraviolet multi-object spectrograph and is a joint collaboration
between Caltech, JPL, LAM, CNES, Columbia, the University of Arizona, and NASA.
The improved detector technology that was tested on FIREBall-2 can be applied
to any UV mission. We discuss the results of the flight and detector
performance. We will also discuss the utility of sub-orbital platforms (both
balloon payloads and rockets) for testing new technologies and proof-of-concept
scientific ideasComment: Submitted to the Proceedings of SPIE, Defense + Commercial Sensing
(SI19
FIREBall-2: flight preparation of a proven balloon payload to image the intermediate redshift circumgalactic medium
FIREBall-2 is a stratospheric balloon-borne 1-m telescope coupled to a UV
multi-object slit spectrograph designed to map the faint UV emission
surrounding z~0.7 galaxies and quasars through their Lyman-alpha line emission.
This spectro-imager had its first launch on September 22nd 2018 out of Ft.
Sumner, NM, USA. Because the balloon was punctured, the flight was abruptly
interrupted. Instead of the nominal 8 hours above 32 km altitude, the
instrument could only perform science acquisition for 45 minutes at this
altitude. In addition, the shape of the deflated balloon, combined with a full
Moon, revealed a severe off-axis scattered light path, directly into the UV
science detector and about 100 times larger than expected. In preparation for
the next flight, and in addition to describing FIREBall-2's upgrade, this paper
discusses the exposure time calculator (ETC) that has been designed to analyze
the instrument's optimal performance (explore the instrument's limitations and
subtle trade-offs)
FIREBall-2: The Faint Intergalactic Medium Redshifted Emission Balloon Telescope
The Faint Intergalactic Medium Redshifted Emission Balloon (FIREBall) is a
mission designed to observe faint emission from the circumgalactic medium of
moderate redshift (z~0.7) galaxies for the first time. FIREBall observes a
component of galaxies that plays a key role in how galaxies form and evolve,
likely contains a significant amount of baryons, and has only recently been
observed at higher redshifts in the visible. Here we report on the 2018 flight
of the FIREBall-2 Balloon telescope, which occurred on September 22nd, 2018
from Fort Sumner, New Mexico. The flight was the culmination of a complete
redesign of the spectrograph from the original FIREBall fiber-fed IFU to a
wide-field multi-object spectrograph. The flight was terminated early due to a
hole in the balloon, and our original science objectives were not achieved. The
overall sensitivity of the instrument and telescope was 90,000 LU, due
primarily to increased noise from stray light. We discuss the design of the
FIREBall-2 spectrograph, modifications from the original FIREBall payload, and
provide an overview of the performance of all systems. We were able to
successfully flight test a new pointing control system, a UV-optimized,
delta-doped and coated EMCCD, and an aspheric grating. The FIREBall-2 team is
rebuilding the payload for another flight attempt in the Fall of 2021, delayed
from 2020 due to COVID-19.Comment: 23 Pages, 14 Figures, Accepted for Publication in Ap
Tackling the issue of image processing via plugins: the example of pyds9plugin: ADASS 2021
While several FITS viewer applications improve the way we visualize astronomical data (DS9, Glue, Gaia, etc.), the development of image processing applications remains extremely limited, even though this is just as necessary. Given the diversity of scientific needs, it is essential to tackle efficiently the issue of image processing by gathering contributions from diverse fields of the astronomy community. This community mostly uses popular scientific programming tools such as the Python+Astropy ecosystem. Therefore, Python plugins for existing FITS viewers represent a very interesting way to take up the challenge of developing image processing tools and address the related difficulties. pyds9plugin, a Python DS9 extension for quick-look processing of astronomical images, is designed to do so. This highly interactive extension provides tens of image treatments and analysis that can be generalized automatically to a set of images to turn the plugin into a multiprocessing pipeline. Its design can be easily combined with user-written scripts to allow scientists to add their own Python macros, fitting functions, etc. This article describes the plugin implementation philosophy as well as the main software features. The plugin is available both on Pypi and GitHub, and full documentation including videos is available on pyds9plugin website
CLAUDS, FIREBall : a UV driven approach to understand what is darkening the shiny destiny of galaxies
L'Ă©volution des galaxies est un sujet vivement dĂ©battu mettant en jeu des mĂ©canismes physiques complexes intervenant Ă de multiples Ă©chelles. Toutefois quelques consensus ont Ă©mergĂ© ces derniĂšres dĂ©cennies. Parmi eux, le fait que l'univers ait atteint son pic dâactivitĂ© de formation d'Ă©toiles il y a 10 milliards d'annĂ©es et que son activitĂ© stellaire ne cesse de dĂ©cliner depuis. Les observations multi-longueur dâondes de lâultra violet (UV) Ă lâinfrarouge lointain convergent vers une diminution d'un facteur dix depuis z~2. Le but de cette thĂšse est d'exploiter le relevĂ© UV CLAUDS pour analyser cette pĂ©riode de dĂ©clin de la formation stellaire. En proposant une calibration rĂ©aliste de lâattĂ©nuation de lâUV par la poussiĂšre, nous accĂ©dons aux plus profondes fonctions de taux de formation dâĂ©toile corrigĂ©es de lâextinction jusquâĂ z~2. Malheureusement les phĂ©nomĂšnes de gaz rĂ©gulant la formation d'Ă©toile (accrĂ©tion, outflows) Ă©tant invisibles pour ce type de relevĂ©s, l'observation de ces phĂ©nomĂšnes nĂ©cessite des instruments de nouvelle gĂ©nĂ©ration. La deuxiĂšme partie de cette thĂšse portera sur l'Ă©tude, via lâinstrument UV FIREBall, de l'environnement des galaxies (milieu circum galactique), considĂ©rĂ© comme le lieu de prĂ©dilection pour les Ă©changes gazeux et Ă©nergĂ©tiques entre les galaxies et le MIG. Le spectrographe multi-objets FIREBall, a pour but d'imager l'Ă©mission Lyman alpha autour des galaxies, et dâouvrir la voie pour de nouveaux instruments spatiaux UV. Je prĂ©senterai donc ma participation au dĂ©veloppement de cet instrument (calibration, Ă©valuation des performances) ainsi que l'analyse des rĂ©sultats du dernier vol effectuĂ© en septembre 2018Galaxy evolution is a complex and heavily debated field as it involves mechanisms arising from a complex interplay between internal and external processes, driven by gravity at large scales and baryonic physics at small scales. However, a few consensuses have emerged in recent decades. Among them, the fact that the Universe reached its peak of star formation activity 10 billion years ago and that its stellar activity has been declining ever since. Multi-wavelength observations from ultraviolet (UV) to far-infrared converge towards a decrease of a factor of ten since z~2. This study aims to exploit the CLAUDS UV survey to analyze this period of star formation decline. By proposing a realistic dust attenuation calibration, we obtain the total star formation of each galaxy and thus estimate the cosmic star formation density evolution for different types of galaxies as the Universe evolves. Unfortunately, since gas phenomena regulating star formation (accretion, outflows) are still invisible for these surveys, understanding star formation decline will be extremely challenging without observing the underlying mechanisms with future instruments generations. Consequently, the second part of this thesis focuses on studying the environment of galaxies (circumgalactic medium), which encompasses all exchanges between galaxies and their surroundings. The pathfinder FIREBall-2, a multi-object UV spectrograph aiming at imaging the gas emission around galaxies and pave the way to orbital UV project, had its first flight in 2018. I will present my contribution to the development of this instrument (calibration, performance evaluation) as well as the analysis of the 2018 flight's dat
Editorial
Herbert Vincent, Picouet Patrick. Editorial. In: Hommes et Terres du Nord, 2002/2. DĂ©troits, sous la direction de GĂ©rard Beltrando. pp. 1-2
Editorial
Herbert Vincent, Picouet Patrick. Editorial. In: Hommes et Terres du Nord, 2002/2. DĂ©troits, sous la direction de GĂ©rard Beltrando. pp. 1-2