250 research outputs found
Nopea mittakaava- ja valaistusinvariantti metodi alueiden luokitteluun
This work describes how to find 3D objects in 2D images. The images may contain various illumination conditions and backgrounds. Furthermore the distance and the rotation of the camera with respect to the object can be arbitrary. The method described in this work provides a way to reduce computation time of the 3D object localization problem by searching only from the regions of the image that include a combination of the most common colors of the object. The accuracy and speed of the implementation is tested on images taken under various illuminations and backgrounds.Tämä työ kuvailee miten kolmiulotteisia esineitä voi löytää kaksiulotteisista kuvista. Kuvat voivat sisältää vaihtelevia valaistusolosuhteita ja taustoja. Lisäksi kameran etäisyys ja avaruuskulma suhteessa esineeseen on mielivaltainen.
Tässä työssä esitetty menetelmä antaa tavan vähentää kolmiulotteisen esineen löytämisen laskenta-aikaa etsimällä ainoastaan niistä kohdista, joissa on yhdistelmä esineen yleisimpiä värejä. Menetelmän tarkkuus ja nopeus on testattu kuvilla, jotka on otettu erilaisilla valaistuksilla ja taustoilla
The climate change movement and political parties: Mechanisms of social media and interaction during the 2019 electoral period in Finland
Peer reviewe
A connection between -ray and parsec-scale radio flares in the blazar 3C 273
We present a comprehensive 5-43 GHz VLBA study of the blazar 3C 273 initiated
after an onset of a strong -ray flare in this source. We have analyzed
the kinematics of new-born components, light curves, and position of the
apparent core to pinpoint the location of the -ray emission. Estimated
location of the -ray emission zone is close to the jet apex, 2 pc to 7
pc upstream from the observed 7 mm core. This is supported by ejection of a new
component. The apparent core position was found to be inversely proportional to
frequency. The brightness temperature in the 7 mm core reached values up to at
least K during the flare. This supports the dominance of particle
energy density over that of magnetic field in the 7 mm core. Particle density
increased during the radio flare at the apparent jet base, affecting
synchrotron opacity. This manifested itself as an apparent core shuttle along
the jet during the 7 mm flare. It is also shown that a region where optical
depth decreases from to spans over several parsecs along
the jet. The jet bulk flow speed estimated at the level of 12c on the basis of
time lags between 7 mm light curves of stationary jet features is 1.5 times
higher than that derived from VLBI apparent kinematics analysis.Comment: Accepted for publication in MNRAS. 17 pages, 15 figures, 10 tables,
with supplementary materials attache
Jumalan pitkät hautajaiset Maallistuminen kristillisen uskon ominaispiirteenä Gianni Vattimon filosofiassa
3D modelling of the dolerite dyke network within the Siilinjärvi phosphate deposit
Non peer reviewe
Observing the Time Evolution of the Multi-Component Nucleus of 3C\,84
The advent of global mm-band Very Long Baseline Interferometry (VLBI) in
recent years has finally revealed the morphology of the base of the two most
prominent nearby, bright, extragalactic radio jets in M\,87 and 3C\,84. The
images are quite surprising considering the predictions of jet theory and
current numerical modeling. The jet bases are extremely wide compared to
expectations and the nucleus of 3C\,84 is very complicated. It appears as a
double in 86\,GHz observations with 50\,as resolution and a triple nucleus
with 30\,as resolution with space-based VLBI by RadioAstron at 22\,GHz.
What is even odder is that the double and triple are arranged along an
east-west line that is approximately orthogonal to the north-south large scale
jet on 150\,as 4\,mas scales. We explore the emergence of an
(east-west) double nucleus in the lower resolution 43\,GHz Very Long Baseline
Array (VLBA) imaging from August 2018 to April 2020. The double is marginally
resolved. We exploit the east-west resolution associated with the longest
baselines, \,mas, to track a predominantly east-west separation
speed of \,c. We estimate that the observed mildly
relativistic speed persists over a de-projected distance of
times the central, supermassive black hole, gravitational radius (\,lt-yrs) from the point of origin.Comment: To appear in Ap
The Relation between Radio Polarization and Gamma-ray Emission in AGN Jets
We have compared the parsec-scale jet linear polarization properties of the
Fermi LAT-detected and non-detected sources in the complete
flux-density-limited (MOJAVE-1) sample of highly beamed AGN. Of the 123 MOJAVE
sources, 30 were detected by the LAT during its first three months of
operation. We find that during the era since the launch of Fermi, the
unresolved core components of the LAT-detected jets have significantly higher
median fractional polarization at 15 GHz. This complements our previous
findings that these LAT sources have higher apparent jet speeds, brightness
temperatures and Doppler factors, and are preferentially found in higher
activity states.Comment: 6 pages, 3 figures, to appear in the proceedings of "High Energy
Phenomena In Relativistic Outflows II" (Buenos Aires, Argentina, October
26-30, 2009) International Journal of Modern Physics
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